### Create a StudySoup account

#### Be part of our community, it's free to join!

Already have a StudySoup account? Login here

# Weekly assignments 1-7 1220

Mizzou

GPA 3.0

### View Full Document

## About this Document

## 118

## 0

## Popular in College Physics II

## Popular in Physics 2

This page Bundle was uploaded by Dragon Note on Friday March 18, 2016. The Bundle belongs to 1220 at University of Missouri - Columbia taught by Y Zhang in Spring 2016. Since its upload, it has received 118 views. For similar materials see College Physics II in Physics 2 at University of Missouri - Columbia.

## Similar to 1220 at Mizzou

## Popular in Physics 2

## Reviews for Weekly assignments 1-7

### What is Karma?

#### Karma is the currency of StudySoup.

#### You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 03/18/16

Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Weekly Assignment 01 Due 900pm on Friday January 29 2016 To understand how points are awarded read the Grading Policy for this assignment Conceptual Exercise 1911 Four pairs of conducting spheres all with the same radius are shown in the figure along with the net charge placed on them initially The spheres in each pair are now brought into contact allowing charge to transfer between them Part A Rank the pairs of spheres in order of decreasing magnitude of the charge transferred Rank from largest to smallest To rank items as equivalent overlap them ANSWER 10f19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Correct Problem 1923 Part A Given that q 13 LLC and d 18 cm find the direction and magnitude of the net electrostatic force exerted on the point charge ql in the figure 1 g m I mm h trim nn u u Express your answer using two significant figures I A H LII iji H ANSWER F 59 N All attempts used correct answer displayed Part B ANSWER 2 of 19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl toward the left toward the right Correct Problem 1927 Suppose the charge 12 in the figure can be moved left or right h i W U Elm h 2 I111 along the line connecting the charges ql and q3 w cw 1 Q r J Iquot ll 39 39 139 quotI Part A Given that q 12 LLC find the distance from ql where q2 experiences a net electrostatic force of zero The charges ql and q3 are separated by a fixed distance of 36 cm Express your answer using two significant figures ANSWER 13 13 cm Correct Problem 1931 Part A Find the direction and magnitude of the net electrostatic force exerted on the point charge 12 in the figure Let q I 26uC and d 350m 33 flair r I E 3U Express your answer using two significant figures quot quot I I I I I I I I I I I illi 3 of19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl ANSWER Fnet 44 N All attempts used correct answer displayed Part B Express your answer using three significant figures ANSWER 0 175 O counterclockwise from q2q3 direction Correct Electric Field Conceptual Question Part A For the charge distribution provided indicate the region A to E along the horizontal axis where a point exists at which the net electric field is zero If no such region exists on the horizontal axis choose the last option nowhere y rrr Hint 1 Zeros of the electric field The net electric field can only be zero if the electric fields due to the two charges point in opposite directions and have equal magnitudes Therefore first determine the regions where the two constituent electric fields point in opposite directions Then in each region determine whether a point exists where the fields have equal magnitude If there is such a point then select that region ANSWER 4 of 19 3222016 530 PM Weekly Assignment 01 50f19 https sessionmasteringphysics commyct as signmentPrintVieW displ mUOwgt nowhere Correct Part B For the charge distribution provided indicate the region A to E along the horizontal axis where a point exists at which the net electric field is zero If no such region exists on the horizontal axis choose the last option nowhere Hint 1 Zeros of the electric field The net electric field can only be zero if the electric fields due to the two charges point in opposite directions and have equal magnitudes Therefore first determine the regions where the two constituent electric fields point in opposite directions Then in each region determine whether a point exists where the fields have equal magnitude If there is such a point then select that region Hint 2 Determine the regions where the electric fields could cancel In which regions do the electric fields from the two source charges point in opposite directions List all the correct answers in alphabetical order ANSWER BCD Hint 3 Consider the magnitude of the electric field For each of the three regions found in the previous hint determine whether it is possible for the magnitudes to be equal As an example consider the point directly between the two charges Which charge produces the largest magnitude field directly between the two charges 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl ANSWER the charge on the right the charge on the left neither because they have the same magnitude ANSWER mUOwgt nowhere Correct Part C For the charge distribution provided indicate the region A to E along the horizontal axis where a point exists at which the net electric field is zero If no such region exists on the horizontal axis choose the last option nowhere Hint 1 Zeros of the electric field The net electric field can only be zero if the electric fields due to the two charges point in opposite directions and have equal magnitudes Therefore first determine the regions where the two constituent electric fields point in opposite directions Then in each region determine whether a point exists where the fields have equal magnitude If there is such a point then select that region ANSWER 6 of 19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl mUOwgt nowhere Correct Part D For the charge distribution provided indicate the region A to E along the horizontal axis where a point exists at which the net electric field is zero 1 er Etf Hint 1 Zeros of the electric field The net electric field can only be zero if the electric fields due to the two charges point in opposite directions and have equal magnitudes Therefore first determine the regions where the two constituent electric fields point in opposite directions Then in each region determine whether a point exists where the fields have equal magnitude If there is such a point then select that region ANSWER mUOwgt Nowhere along the finite x axis 70f19 3222016 530 PM Weekly Assignment 01 80f19 https sessionmasteringphysics commyct as signmentPrintVieW displ Correct Electric Field due to Multiple Point Charges Two point charges are placed on the X axis The first charge q1 800 nC is placed a distance 160 m from the origin along the positive X axis the second charge 12 600 11C is placed a 1 I I r i r r P distance 900 In from the origin along the negative X axns H in m h W iii1 m in I ml in l l 1quot LEE El E3 flit l illll if t Hittiltm r 7 I itt llljtfll Part A Calculate the electric field at point A located at coordinates 0 m 120 m Give the X and ycomponents of the electric field as an ordered pair Express your answer in newtons per coulomb to three significant figures Hint 1 How to approach the problem Find the contributions to the electric field at point A separately for ql and 12 then add them together using vector addition to find the total electric field at that point You will need to use the Pythagorean theorem to find the distance of each charge from point A Hint 2 Calculate the distance from each charge to point A Calculate the distance from each charge to point A Enter the two distances separated by a comma in meters to three significant figures ANSWER TA17quotA2 200150 I11 Correct Hint 3 Determine the directions of the electric fields Which of the following describes the directions of the electric fields EA1 and EA2 created by charges ql and q2 at point A 3222016 530 PM Weekly Assignment 01 90f19 https sessionmasteringphysics commyct as signmentPrintVieW displ ANSWER E39Al points up and left and EM points up and right EA1 points up and left and EA2 points down and left EM points down and right and EM points up and right EA1 points down and right and EA2 points down and left Correct In this case the electric fields due to the two charges have both X and y components that are nonzero To find the total field add these two components separately Hint 4 Calculate the components of EM Calculate the X and y components of the electric field EAl at point A due to charge ql Express your answers in newtons per coulomb separated by a comma to three significant figures Hint 1 Calculate the magnitude of the total field Calculate the magnitude of the field EA1 at point A due to charge ql only Express your answer in newtons per coulomb to three significant figures ANSWER EA1 0180 NC Answer Requested Hint 2 How to find the components of the total field Once you have found the magnitude of the field use trigonometry to determine the X and y components of the field The electric field of a positive point charge points directly away from the charge so the direction of the electric field at point A due to charge ql will be along the line joining the two Use the position coordinates of ql and point A to find the angle that the line joining the two makes with the X or y axis Then use this angle to resolve the electric field vector into components ANSWER EAlmaEA1y O1440108 NC Incorrect Try Again 4 attempts remaining Hint 5 Calculate the components of EA2 Calculate the X and y components of the electric field at point A due to charge q2 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Express your answers in newtons per coulomb separated by a comma to three significant figures Hint 1 Calculate the magnitude of the total field Calculate the magnitude of the field EA2 at point A due to charge q2 only Express your answer in newtons per coulomb to three significant figures ANSWER EA2 0240 NC Hint 2 How to find the components of the total field Once you have found the magnitude of the field use trigonometry to determine the X and y components of the field The electric field of a positive point charge points directly away from the charge so the direction of the electric field at point A due to charge qg will be along the line joining the two Use the position coordinates of 12 and point A to find the angle that the line joining the two makes with the X or y axis Then use this angle to resolve the electric field vector into components ANSWER EAZwEA2y 01440192 NC ANSWER EAmEAy 00300 NC Correct Part B An unknown additional charge q3 is now placed at point B located at coordinates O In 150 In Find the magnitude and sign of q3 needed to make the total electric field at point A equal to zero Express your answer in nanocoulombs to three significant figures Hint 1 How to approach the problem You have already calculated the electric field at point A due to ql and q2 Now find the charge q3 needed to make an opposite field at point A so when the two are added together the total field is zero Hint 2 Determine the sign of the charge Which sign of charge q3 is needed to create an electric field EA3 that points in the opposite direction of the total field due to the other two charges ql and q2 ANSWER 10 0f19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl positive nega ve Hint 3 Calculating the magnitude of the new charge Keep in mind that the magnitude of the field due to q3 is EA3 kqg 13 and the field must be equal in magnitude to the field due to charges Q1 and q2 ANSWER q3 0300 110 Correct Problem 1947 An object with a charge of 32 LLC and a mass of 15gtlt1O392 kg experiences an upward electric force due to a uniform electric field equal in magnitude to its weight Part A Find the magnitude of the electric field Express your answer using two significant figures ANSWER E 46x104 NC Correct 110f19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Part B Find the direction of the electric field ANSWER upward downward to the left to the right Correct Part C If the electric charge on the object is doubled while its mass remains the same find the direction and magnitude of its acceleration Express your answer using three significant figures ANSWER a 981 ms2 All attempts used correct answer displayed Part D If the electric charge on the object is doubled while its mass remains the same find the direction and magnitude of its acceleration ANSWER upward downward to the left to the right Correct Visualizing Electric Fields Learning Goal To understand the nature of electric fields and how to draw field lines 12 of19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Electric field lines are a tool used to visualize electric fields A field line is drawn beginning at a positive charge and ending at a negative charge Field lines may also appear from the edge of a picture or disappear at the edge of the picture Such lines are said to begin or end at in nity The field lines are directed so that the electric field at any point is tangent to the field line at that point shows two different ways to visualize an electric field On the left vectors are drawn at various points to show the direction and magnitude of the electric field On the right electric field lines 1 depict the same situation Notice that as stated above the electric quot3 field lines are drawn such that their tangents point in the same gt T A quot an direction as the electric field vectors on the left Because of the quot nature of electric fields field lines never cross Also the vectors T shrink as you move away from the charge and the electric field lines spread out as you move away from the charge The spacing between electric field lines indicates the strength of the electric field just as the length of vectors indicates the strength of the electric field The greater the spacing between field lines the L weaker the electric field Although the advantage of field lines over in field vectors may not be apparent in the case of a single charge electric field lines present a much less cluttered and more intuitive picture of more complicated charge arrangements PartA Which ofthe following panels labelled A B C and D in 3 correctly depicts the field lines from an infinite uniformly w negatively charged sheet Note that the sheet is being viewed edgeon in all pictures Hint 1 Description of the field Recall that the field around an infinite charged sheet is always perpendicular to the sheet and that the field strength does not change regardless of distance from the sheet ANSWER 0003 13 of19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Correct Part B nwhat is wrong with panel B Pick only those statements fit H a an that apply to panel B in H a 1 i 1 9 a 5 Check all that apply H ix T n T a a n i 5 l 39l quot33 quot LL la a L 1 ll u we a a r a v r a l I EH 5 a H F an ANSWER Field lines cannot cross each other The field lines should be parallel because of the sheets symmetry The field lines should spread apart as they leave the sheet to indicate the weakening of the field with distance The field lines should always end on negative charges or at infinity Correct Part C Which ofthe following panels labelled A B C and D in A I i b shows the correct electric field lines for an electric dipole my 39 an f i j 9 ta 2 If 1 r H g 1 i e l Hr EV u quottask quotquot t l quota p 39 a i H l a I 39 a ANSWER 14 0f19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl DOW Correct This applet shows two charges You can alter the charge on each independently or alter the distance between them You should try to get a feeling for how altering the charges or the distance affects the field lines Part D In what is wrong with panel D Pick only those statements A H 3 that apply to panel D a i g 39 Check all that apply 1 Z j jei j 1 la J 7 quotxx39 fquoti a so jl l Di H l in 313 f 3 a 53 P in rt a E ANSWER Field lines cannot cross each other The field lines should turn sharply as you move from one charge to the other The field lines should be smooth curves The field lines should always end on negative charges or at infinity 15 0f19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Correct 9 Even in relatively simple setups as in the figure shown electric field lines are quite helpful for understanding the field qualitatively understanding the general direction in which a certain charge will move from a specific position identifying locations where the field is roughly zero or where the field points a specific direction etc A good figure with electric field lines can help you to organize your thoughts as well as check your calculations to see whether they make sense Part E In the electric field lines are shown for a system of two point charges QA and QB Which of the following could represent Jr is the magnitudes and signs of QA and QB 3 7 In the following take q to be a positive quantity 1 Pr H D M H x F L a Liquot L 5 f i a l E l 5 in r H La i QH a H g a a JFK l Pl m I ll b l a ANSWER QA 61 QB q QA 7q QB 3q QA 3q QB 7q QA 3q QB 7q QA 7q QB 3q Correct Very far from the two charges the system looks like a single charge with value QA l QB 4q At large enough distances the field lines will be indistinguishable from the field lines due to a single point charge 4q 16 0f19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Charging a Grounded Conducting Rod Learning Goal To understand interactions between a grounded conductor and a charged ball that is repeatedly brought into contact with it This problem explores the behavior of charge on grounded conductors We take as an example a long conducting rod suspended by conducting wires that are connected to ground Assume that the rod is initially electrically neutral For convenience we will refer to the left end of the rod as end A and the right end of the rod as end B In the answer options for this problem quotstrongly attractedrepelledquot means quotattractedrepelled with a force of magnitude similar to that which would exist between two charged ballsquot 1 lF39l ll 41 Illl 1 ua a ll il flit huh Fur Part A A small metal ball is given a negative charge then brought near ie within about 110 the length of the rod to end A of the rod What happens to end A of the rod when the ball approaches it closely this first time Select the expected behavior Hint 1 The key property of conductors The key property of a conductor is that the charges are free to move around inside in response to internal electric fields in a static situation they will arrange so that the internal field is zero Hint 2 How much charge moves to end A It is stated that the ball approaches the end of the rod much closer than the length of the rod Therefore if points down the rod several times the distance of approach but still much closer to end A than end B are to experience no electric field the charge on end A of the rod must be comparable in magnitude to the charge on the ball so that their fields will cancel ANSWER 17 of19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl strongly repelled strongly attracted weakly attracted weakly repelled neither attracted nor repelled Correct Now consider what happens when the small metal ball is repeatedly given a negative charge and then brought into contact with end A of the rod Part B After a great many contacts with the charged ball how is any charge on the rod arranged when the charged ball is far away Select the best description Hint 1 The rod is grounded The rod is grounded and the charged ball is far away ie it produces a negligible electric field in the vicinity of the rod Any charge previously transferred to the rod has been conducted to ground and there are no electric fields around to induce any charge in the rod ANSWER positive charge on end B and negative charge on end A negative charge spread evenly on both negative charge on end A with end B remaining neutral both ends neutral positive charge spread evenly on both Correct Part C How does end A of the rod react when the recharged ba approaches it after a great many previous contacts with end A Select the expected behavior Hint 1 The rod is a grounded conductor Any charge previously transferred to the conducting rod has been conducted to ground 18 of19 3222016 530 PM Weekly Assignment 01 httpssessionmasteringphysicscommyctassignmentPrintVieWdispl ANSWER strongly repelled strongly attracted weakly attracted weakly repelled neither attracted nor repelled Correct Part D How does end B of the rod react when the charged ball approaches it after a great many previous contacts with end A Select the expected behavior Hint 1 The rod is a grounded conductor Any charge previously transferred to the conducting rod has been conducted to ground ANSWER strongly repelled strongly attracted weakly attracted weakly repelled neither attracted nor repelled Correct Score Summary Your score on this assignment is 752 You received 827 out of a possible total of 11 points 19 of19 3222016 530 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Weekly Assignment 02 Due 900pm on Monday February 1 2016 To understand how points are awarded read the Grading Policy for this assignment PmMem203 A uniform electric field of magnitude 60gtlt105 NC points in the positive a direction Part A Find the change in electric potential between the origin and the point 0 60 m Express your answer using one significant figure ANSWER AVOV Correct Part B Find the change in electric potential between the origin and the point 60 In 0 Express your answer using two significant figures ANSWER AV 36gtlt1O6 V All attempts used correct answer displayed Part C Find the change in electric potential between the origin and the point 60 In 60 In Express your answer using two significant figures ANSWER AV 36gtlt1O6 V Correct PmMem202 A uniform electric field of magnitude 95x105 NC points in the positive 8 direction 1 of 17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Part A Find the change in electric potential energy of a 60MC charge as it moves from the origin to the point 0 60 m Express your answer using one significant figure ANSWER AU0J All attempts used correct answer displayed Part B Find the change in electric potential energy of a 60MC charge as it moves from the origin to the point 60 m 0 Express your answer using two significant figures ANSWER AU 34 J Correct Part C Find the change in electric potential energy of a 60MC charge as it moves from the origin to the point 60 m 60 m Express your answer using two significant figures ANSWER AU 34 J Correct Problem 2010 A uniform electric field with a magnitude of 6000 N C points in the positive 1 direction Part A Find the change in electric potential energy when a 115uC charge is moved 500 cm in the positive as direction ANSWER 2of17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl AU 345gtlt1o3 J Correct Part B Find the change in electric potential energy when a 115uC charge is moved 500 cm in the negative 1 direction ANSWER AU 345x103 J Correct Part C Find the change in electric potential energy when a 115uC charge is moved 500 cm in the positive y direction Express your answer using one significant figure ANSWER AUOJ Correct Problem 2018 Part A Calculate the speed of a proton after it accelerates from rest through a potential difference of 220 V Express your answer using two significant figures ANSWER vp 20x105 ms Correct Part B Calculate the speed of an electron after it accelerates from rest through a potential difference of 220 V 3 of 17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Express your answer using two significant figures ANSWER ve 87X106 ms Correct Speed of an Electron in an Electric Field Two stationary positive point charges charge 1 of magnitude 400 11C and charge 2 of magnitude 200 nC are separated by a distance of 550 cm An electron is released from rest at the point midway between the two charges and it moves along the line connecting the two charges Part A What is the speed v nal of the electron when it is 100 cm from charge 1 Express your answer in meters per second Hint 1 How to approach the problem Only the final speed of the electron is needed so an easy way to solve this problem is by using energy techniques Since the only force that acts on the electron is the conservative electric force mechanical energy is conserved Thus find the potential energy at the initial and final positions of the electron from the expression of the potential due to a collection of point charges Also you can easily determine the initial kinetic energy of the electron since it is released from rest Now you have enough information to write the equation of conservation of energy and calculate the speed of the electron from its final kinetic energy Hint 2 Calculate the potential at the midpoint What is the potential Vmid at the midpoint between the two stationary positive charges Express your answer numerically in volts Hint 1 Electric potential The potential V due to a single point charge is VZLQ 471150 7 where 60 885gtlt103912 C2N m2 1 is the distance from the point charge to the point at which the potential is calculated and q is the charge If instead of a single point charge there is a collection of point charges the total potential is given by the sum of the potentials due to each charge Hint 2 Find the potential due to charge 1 What is the potential Vmidl at the midpoint due to charge 1 alone Express your answer numerically in volts ANSWER 4 of 17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Vmid1 131 V ANSWER Vmid 196 V Hint 3 Calculate the initial potential energy Calculate the potential energy Uinit of the electron at the midpoint between the two stationary positive charges using the potential at that point Express your answer numerically in joules Hint 1 How to find the potential energy from the potential Recall that the potential energy U associated with a test charge q is related to the potential V by the equation U qV In this case the test charge is the electron ANSWER Uinit 314gtlt1O 17 J Hint 4 Calculate the initial kinetic energy Calculate the initial kinetic energy Kinit of the electron at the midpoint between the two stationary positive charges Express your answer numerically in joules Hint 1 Initial velocity of the electron Recall that the electron is initially at rest thus its inital velocity is zero ANSWER Kim 0 J Hint 5 Calculate the final potential energy Calculate the potential energy U na of the electron at its final position a point along the line connecting the positive stationary charges at distance 100 cm from charge 1 Express your answer in joules Hint 1 Calculate the potential at the final position of the electron Calculate the potential V nal at the final position of the electron that is at a point along the line connecting the positive stationary charges 100 cm from charge 1 5 of 17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Express your answer numerically in volts ANSWER Ifinal 400 V ANSWER U nal 639gtlt1O3917 J Hint 6 Putting it all together Once you know the initial kinetic energy Kinit the initial potential energy Uinit and the final potential energy U na of the electron you can calculate its final kinetic energy Kfjnal by applying conservation of energy Kinit Uinit K final Ufinal Finally use the equation for the kinetic energy of a particle in this case the moving electron to calculate its speed since the mass of the electron is a known constant 911 gtlt1O 31 kg ANSWER U na1 845gtlt lO6 IIIS Correct Note that the electric field between the two charges is not constant so the easiest way to do these calculations is to use conservation of energy It is possible to integrate along the path of the electron using the electric field as a function of the distance from each charge but this is much more difficult to do and not necessary for the problem Problem 2034 A charge of 335 uC is held fixed at the origin A second charge of 335 uC is released from rest at the position 125 m 0570 In Part A If the mass of the second charge is 239 g what is its speed when it moves infinitely far from the origin ANSWER U 784 ms Correct 6 of 17 3222016 532 PM Weekly Assignment 02 Part B At what distance from the origin does the second charge attain half the speed it will have at infinity ANSWER 7quot 183 m All attempts used correct answer displayed https sessionmasteringphysics commyct as signmentPrintVieW displ Problem 2036 A charge of 2560 MO is located at 2910 m 4540 m and a charge of 1720 uC is located at 2761 m 0 Part A Find the electric potential at the origin Express your answer using three significant figures ANSWER V 133gtlt1O3 V Correct Part B There is one point on the line connecting these two charges where the potential is zero Find this point Express your answers using three decimal places separated by a comma ANSWER my O4821824 m All attempts used correct answer displayed Problem 2036b Solutions Learning Goal 7of17 at J 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl DH 3 0 lt A lt3 3quot r i n x 9 Vquot W H 3 g 0 x 5 O S m u 3 E 7 LE E V w v n I w P 3 quot7 m E VT39 N 1 j A N Cw i gt2 9 7 E N S j Iv quot w E x lt H on lt50 4 ii i a h i 0 no 2 H C C M F3 1 J S f I 5 gt3 Part A Is it helpful ANSWER Essay answers are limited to about 500 words 3800 characters maximum including spaces 3785 Characters remaining none provided Problem 2039 Part A 8 of 17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Find the electric potential at point P in the figure u45 FE at l t f l 1quot f I 539 it I g x r l quota L r I i 125 m g l a 135 m 3 1 r I a f I i rquot it if I at r I t it I quota r t 3i 1 35 Juli l 5 11 412 Juli ANSWER VP 767X104 V Correct Part B Suppose the three charges shown in the figure are held in place A fourth charge with a charge of 690 uC and a mass of 450 g is released from rest at point P What is the speed of the fourth charge when it has moved infinitely far away from the other three charges ANSWER v 153 ms All attempts used correct answer displayed The Capacitor as an EnergyStoring Device Learning Goal To understand that the charge stored by capacitors represents energy to be able to calculate the stored energy and its changes under different circumstances An airfilled parallelplate capacitor has plate area A and plate separation d The capacitor is connected to a battery that creates a constant voltage V Part A Find the energy U0 stored in the capacitor Express your answer in terms of A d V and 60 Remember to enter 60 as epsilon0 Hint 1 Formula for the energy of a capacitor 9 of 17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Recall that the equation for the energy of a capacitor is U CV2 ANSWER U A V2 0 EOZ d Correct Part B The capacitor is now disconnected from the battery and the plates of the capacitor are then slowly pulled apart until the separation reaches 3d Find the new energy U1 of the capacitor after this process Express your answer in terms of A d V and 60 Hint 1 What quantity remains constant What characteristic of the capacitor does not change in this process ANSWER charge voltage between the plates capacHance energy Hint 2 Find the charge on the capacitor What is the charge Q that resides on the plates of the capacitor Express your answer in terms of some or all of the variables V A and d Remember to enter 60 as epsilon0 ANSWER V2460 Q d Hint 3 How does the capacitance change How does the capacitance change in this process ANSWER 10 0f17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl remains constant increases by a factor of 3 decreases by a factor of 3 increases by a factor of 9 decreases by a factor of 9 Hint 4 What is the formula for the energy Which ofthe following formulas is most useful in finding U1 for this situation ANSWER JV2 2 QV T Q2 E ANSWER 2 U1 31460 g d Correct The increase in energy of the capacitor comes from the external work that must be done to pull the plates apart Keep in mind that the plates have opposite charges and attract each other some work must be done by an external agent to pull them apart Part C The capacitor is now reconnected to the battery and the plate separation is restored to d A dielectric plate is slowly moved into the capacitor until the entire space between the plates is filled Find the energy U2 of the dielectricfilled capacitor The capacitor remains connected to the battery The dielectric constant is K Express your answer in terms of A d V K and 60 ANSWER 2 U2 KA 0 Correct 110f17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Problem 2053 A parallelplate capacitor is made from two aluminumfoil sheets each 49 cm wide and 60 m long Between the sheets is a Teflon strip of the same width and length that is 44gtlt10 2 mm thick Part A What is the capacitance of this capacitor The dielectric constant of Teflon is 21 Express your answer using two significant figures ANSWER C39 012 uF All attempts used correct answer displayed Problem 2054 A parallelplate capacitor is constructed with circular plates of radius 58gtlt10392 In The plates are separated by 024 mm and the space between the plates is filled with a dielectric with dielectric constant H When the charge on the capacitor is 13 MC the potential difference between the plates is 800 V Part A Find the value of the dielectric constant IS Express your answer using two significant figures ANSWER FL 42 Correct Energy in Capacitors and Electric Fields Learning Goal To be able to calculate the energy of a charged capacitor and to understand the concept of energy associated with an electric field The energy of a charged capacitor is given by U QVZ where Q is the charge of the capacitor and V is the potential difference across the capacitor The energy of a charged capacitor can be described as the energy associated with the electric field created inside the capacitor In this problem you will derive two more formulas for the energy of a charged capacitor you will then use a parallelplate capacitor as a vehicle for obtaining the formula for the energy density associated with an electric field It will be useful to recall the definition of capacitance C QV and the formula for the capacitance of a parallelplate capacitor 12 of17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl C 60 Ad where A is the area of each of the plates and d is the plate separation As usual 60 is the permittivity of free space First consider a capacitor of capacitance C that has a charge Q and potential difference V Part A Find the energy U of the capacitor in terms of C and Q by using the definition of capacitance and the formula for the energy in a capacitor Express your answer in terms of C and Q ANSWER Correct Part B Find the energy U of the capacitor in terms of C and V by using the definition of capacitance and the formula for the energy in a capacitor Express your answer in terms of C and V ANSWER 0V2 U 2 Correct All three of these formulas are equivalent 2 20 2 39 Depending on the problem one or another may be more convenient to use However any one of them would give you the correct answer Note that these formulas work for any type of capacitor Part C A parallelplate capacitor is connected to a battery The energy of the capacitor is U0 The capacitor remains connected to the battery while the plates are slowly pulled apart until the plate separation doubles The new energy of the capacitor is U Find the ratio UUO Hint 1 Determine what remains constant As the plates are being pulled apart slowly what quantity or quantities remain constant ANSWER 13 0f17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl capacitance only voltage only charge only both voltage and capacitance both voltage and charge Hint 2 Identify which formula to use Which formula for energy is most convenient to use in this case ANSWER QV 2 Q2 E CV2 2 ANSWER U U0 05 Correct Part D A parallelplate capacitor is connected to a battery The energy of the capacitor is U0 The capacitor is then disconnected from the battery and the plates are slowly pulled apart until the plate separation doubles The new energy of the capacitor is U Find the ratio U U0 Hint 1 Determine what remains constant As the plates are being pulled apart what quantity or quantities remain constant ANSWER capacitance only voltage only charge only both voltage and charge both voltage and capacitance 14 0f17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Hint 2 Identify which formula to use Which formula for energy is most convenient to use in this case ANSWER QV 2 Q2 E 0V2 2 ANSWER U U0 39 2 Correct In this part of the problem you will express the energy of various types of capacitors in terms of their geometry and voltage Part E A parallelplate capacitor has area A and plate separation d and it is charged to voltage V Use the formulas from the problem introduction to obtain the formula for the energy U of the capacitor Express your answer in terms of A d V and appropriate constants ANSWER AV2 U 60 2d Correct Let us now recall that the energy of a capacitor can be thought of as the energy of the electric field inside the capacitor The energy of the electric field is usually described in terms of energy density u the energy per unit volume A parallelplate capacitor is a convenient device for obtaining the formula for the energy density of an electric field since the electric field inside it is nearly uniform The formula for energy density can then be written as U Ll2 where U is the energy of the capacitor and V is the volume of the capacitor not its voltage Part F A parallelplate capacitor has area A and plate separation d and it is charged so that the electric field inside is E Use the formulas from the problem introduction to find the energy U of the capacitor 15 of17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Express your answer in terms of A d E and appropriate constants Hint 1 How to approach the problem Recall that for the uniform electric field E between the plates of a parallelplate capacitor V Ed where V is the potential difference between the plates and d is the distance between the two plates You can use this relation to rewrite the equation for energy U CV2 in terms of the electric field and the geometry of the capacitor ie the area of the plates and the distance between them ANSWER 2 U 60 Ad2E Correct As mentioned before we can think of the energy of the capacitor as the energy of the electric eld inside the capacitor Part G Find the energy density u of the electric field in a parallelplate capacitor The magnitude of the electric field inside the capacitor is E Express your answer in terms of E and appropriate constants Hint 1 How to approach the problem Since the electric field outside a parallelplate capacitor is essentially zero the volume that you are looking for is the volume of the space between the two plates Hint 2 Volume between the plates Recall that the volume V of a solid with two parallel bases of the same shape and sides perpendicular to the bases is given by V 2 Ah where A is the area of each of the bases and h is the distance between the bases Note that the space between the plates of a parallelplate capacitor is such a solid ANSWER Correct Note that the answer for u does not contain any reference to the geometry of the capacitor A and d do not appear in the formula In fact the formula 6022 2 describes the energy density in any electrostatic field whether created by a capacitor or any other source 16 0f17 3222016 532 PM Weekly Assignment 02 https sessionmasteringphysics commyct as signmentPrintVieWdispl Problem 2069 An electronic flash unit for a camera contains a capacitor with a capacitance of 900 uF When the unit is fully charged and ready for operation the potential difference between the capacitor plates is 330 V Part A What is the magnitude of the charge on each plate of the fully charged capacitor Express your answer using two significant figures ANSWER Q 030 C Correct Part B Find the energy stored in the quotchargedupquot flash unit Express your answer using two significant figures ANSWER U 49J Correct Problem 2067 Part A Find the electric energy density between the plates of a 225uF parallelplate capacitor The potential difference between the plates is 335 V and the plate separation is 0300 mm ANSWER 013 552 Jm3 Correct Score Summary Your score on this assignment is 754 You received 1433 out of a possible total of 19 points 17 of17 3222016 532 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl Weekly Assignment 03 Due 900pm on Monday February 8 2016 To understand how points are awarded read the Grading Policy for this assignment Problem 2132 IP A 75 W lightbulb operates on a potential difference of 80 V Part A Find the current in the bulb Express your answer using two significant figures ANSWER I 094 A Correct Part B Find the resistance of the bulb Express your answer using two significant figures ANSWER R85Q Correct Part C If this bulb is replaced with one whose resistance is half the value found in part B is its power rating greater than or less than 75 W ANSWER greater than lessthan Correct Part D By what factor 10f13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl ANSWER by a factor of 2 by a factor of 2 by a factor of 2V2 by a factor of 4 Correct Problem 2138 Part A Find the equivalent resistance between points A and B for the group of resistors shown in the figure Suppose R1 65 9132 83QandR3 57Q Express your answer using two significant figures ANSWER R41S2 All attempts used correct answer displayed Problem 2141 Your toaster has a power cord with a resistance of 21 x10quot2 Q connected in series with a 97 Q nichrome heating element The potential difference between the terminals of the toaster is 120 V Part A How much power is dissipated in the power cord l Typesetting math 49 lswer using two significant figures 2 of 13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl ANSWER Powd 32 W Correct Part B How much power is dissipated in the heating element Express your answer using two significant figures ANSWER Phe 15 Correct Problem 2143 A circuit consists of a 120V battery connected to three resistors 43 Q 17 Q and 120 Q in series Part A Find the current that flows through the battery Express your answer using two significant figures ANSWER I 67 mA Correct Part B Find the potential difference across the 43 Q resistor Express your answer using two significant figures ANSWER V1 29 V Correct N Typesetting math 49 3 0f13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl Find the potential difference across the 17 Q resistor Express your answer using two significant figures ANSWER V211 V Correct Part D Find the potential difference across the 120 Q resistor Express your answer using two significant figures ANSWER V3 80 V Correct Problem 2145 A circuit consists of a battery connected to three resistors 70 Q 30 S2 and 170 Q in parallel The total current through the resistors is 17 A Part A Find the emf of the battery Express your answer using two significant figures ANSWER 532V Correct Part B Find the current through 70 Q resistor Express your answer using two significant figures ANSWER I1 045 A H Typesetting math 49 4 of 13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl Correct Part C Find the current through 30 Omega resistor Express your answer using two significant figures ANSWER I2 11 rmA Correct Part D Find the current through 170 Omega resistor Express your answer using two significant figures ANSWER I3 019 rmA Correct Problem 2147 An 87 rm Omega resistor has a current of 075 rm A and is connected in series with a 140 rm Omega resistor Part A What is the emf of the battery to which the resistors are connected Express your answer using two significant figures ANSWER calE 017 rm kV Correct Equivalent Resistance Consider the network of four resistors shown in the diagram where texttipRrm 1R1 200 rm rm Omega texttipRrm 2R2 500 rm rm Omega texttipRrm 3R3 100 rm rm Omega and texttipRrm l Typesetting math 49 lm Omega The resistors are connected to a constant voltage of magnitude texttipVV 5 0f13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl a 3 Part A Find the equivalent resistance texttipRmit ARA of the resistor network Express your answer in ohms Hint 1 How to reduce the network of resistors The network of resistors shown in the diagram is a combination of series and parallel connections To determine its equivalent resistance it is most convenient to reduce the network in successive stages First compute the equivalent resistance of the parallel connection between the resistors texttipRrm 1R1 and texttipRrm 2R2 and imagine replacing the connection with a resistor with such resistance The resulting network will consist of three resistors in series Then find their equivalent resistance which will also be the equivalent resistance of the original network Hint 2 Find the resistance equivalent to texttipRrm 1R1 and texttipRrm 2R2 Find the equivalent resistance texttipRrm 12R12 of the parallel connection between the resistors texttipRrm 1R1 and texttipRrm 2R2 Express your answer in ohms Hint 1 Two resistors in parallel Consider two resistors of resistance texttipRrm aRa and texttipRrm bRb that are connected in parallel They are equivalent to a resistor with resistance texttipRrm eqReq which satisfies the following relation argefrac1Rrm eqfrac1Rrm afrac1Rrm b ANSWER texttipRrm 12R12 143 rm Omega Hint 3 Three resistors in series ConsideLthree resistors of resistance texttipRrm aRa texttipRrm bRb and texttipRrm l Typesetting math 49 6 of 13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl cRc that are connected in series They are equivalent to a resistor with resistance texttipRrm eqReq which is given by Rrm eqRrm aRrm bRrm c ANSWER texttipRmitARA 943 rm Omega Correct Part B Two resistors of resistance texttipRrm 5R5 300 rm rm Omega and texttipRrm 6R6 300 rm rm Omega are added to the network and an additional resistor of resistance texttipRrm 7R7 300 rm rm Omega is connected by a switch as shown in the diagram Find the equivalent resistance texttipRrm BRB of the new resistor network when the switch is open Express your answer in ohms it g it 39 it l n if Ha Ha Hint 1 How to reduce the extended network of resistors Since the switch is open no current passes through the resistor texttipRrm 7R7 which can be ignored then As you did in Part A reduce the network in successive stages Note that the new resistor texttipRrm 5R5 is in series with the resistors texttipRrm 3R3 and texttipRrm 4R4 while the new resistor texttipRrm 6R6 is in series with texttipRrm 1R1 Hint 2 Find the resistance equivalent to texttipRrm 1R1 texttipRrm 2R2 and texttipRrm 6R6 Find the resistance texttipRrm 126R126 equivalent to the resistor connection with texttipRrm 1R1 texttipRrm 2R2 and texttipRrm 6R6 Express your answer in ohms Hint 1 Find the resistance equivalent to texttipRrm 1R1 and texttipRrm 6R6 Find the resistance texttipRrm 16R16 equivalent to the connection between texttipRrm 1R1 and texttipRrm 6R6 Express your answer in ohms Typesetting math 49 7of13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl Hint 1 Two resistors in series Consider two resistors of resistance texttipRrm aRa and texttipRrm bRb that are connected in series They are equivalent to a resistor with resistance texttipRrm eqReq which is given by Rrm eq Rrm aRrm b ANSWER texttipRrm 16R16 500 rm Omega Hint 2 Two resistors in parallel Consider two resistors of resistance texttipRrm aRa and texttipRrm bRb that are connected in parallel They are equivalent to a resistor with resistance texttipRrm eqReq which satisfies the following relation argefrac1Rrm eqfrac1Rrm afrac1Rrm b ANSWER texttipRrm 126R126 250 rm Omega Hint 3 Four resistors in series Consider four resistors of resistance texttipRrm aRa texttipRrm bRb texttipRrm cRc and texttipRrm dRd that are connected in series They are equivalent to a resistor with resistance texttipRrm eqReq which is given by Rrm eqRrm aRrm bRrm cRrm d ANSWER texttipRrm BRB 135 rm Omega Correct Part C Find the equivalent resistance texttipRrm CRC of the resistor network described in Part B when the switch is closed Express your answer in ohms Hint 1 How to reduce the network of resistors when the switch is closed When the switch is closed current passes through the resistor texttipRrm 7R7 therefore the resistor atquoti39istihai na39i39i39rded in the calculation of the equivalent resistance Also when the switch is closed the resistor l Typesettmg math 49 l 8 of 13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl texttipRrm 4R4 is no longer connected in series with the resistors texttipRrm 3R3 and texttipRrm 5R5 as was the case when the switch was open Instead now texttipRrm 4R4 is in parallel with texttipRrm 7R7 and their equivalent resistor will be in series with texttipRrm 3R3 and texttipRrm 5R5 Hint 2 Find the resistance equivalent to texttipRrm 4R4 and texttipRrm 7R7 Find the equivalent resistance texttipRrm 47R47 of the parallel connection between the resistors texttipRrm 4R4 and texttipRrm 7R7 Express your answer in ohms Hint 1 Two resistors in parallel Consider two resistors of resistance texttipRrm aRa and texttipRrm bRb that are connected in parallel They are equivalent to a resistor with resistance texttipRrm eqReq which satisfies the following relation largefrac1Rrm eqfrac1Rrm afrac1Rrm b ANSWER texttipRrm 47R47 210 rm Omega Hint 3 Four resistors in series Consider four resistors of resistance texttipRrm aRa texttipRrm bRb texttipRrm cRc and texttipRrm dRd that are connected in series They are equivalent to a resistor with resistance texttipRrm eqReq which is given by Rrm eqRrm aRrm bRrm cRrm d ANSWER texttipRrm CRC 860 rm Omega Correct Problem 2148 The equivalent resistance between points A and B of the resistors shown in the figure is 26 rm Omega H Typesetting math 49 9 of 13 3222016 537 PM Weekly Assignment 03 https sessionmastcringphysics commyct as signmentPrintVieWdispl Part A Find the value of resistance R Express your answer using two significant figures ANSWER R 19 rmOmega Correct Problem 2149 Part A Find the equivalent resistance between points A and B shown in the figure Consider texttipRrm 1R1 50 rm Omega texttipRrm 2R2 49 rm Omega texttipRrm 3R3 12 rm Omega texttipRrm 4R4 46 rm Omega texttipRrm 5R5 85 rm Omega and texttipRrm 6R6 51 rm Omega rt Express your answer using two significant figures RE ANSWER Rrmeq 17 Omega All attempts used correct answer displayed 1 Heating a Water Bath N Typesetting math 49 10 0f13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl In the circuit in the figure a 20ohm resistor sits inside 107 rm g of pure water that is surrounded by insulating Styrofoam rm 39Illll1391 1 till It Part A If the water is initially at temperature 102 rm l circ C how long will it take for its temperature to rise to 573 rm quotcirc C Use 4190rm Jlkg cdot Cquotcirc as the heat capacity of water and express your answer in seconds using three significant figures Hint 1 How to approach the problem First reduce the system of resistors to a single equivalent resistor then use this simplified circuit to calculate the current flowing through the battery Determine the current flowing through the resistor in the water and calculate its power output Finally use the calculated power output to calculate the time needed to heat the water bath Hint 2 Calculate the resistance of the circuit Calculate the total resistance texttipRrm totalRtotal of the network of resistors shown in the figure Express your answer in ohms using three significant figures Hint 1 Reducing a network of resistors to an equivalent resistor For any network of resistors first look at any section between two junction points in which all resistors are in series and combine them appropriately to obtain the equivalent resistance through that section of the network Next see whether any combined sections are in parallel with each other and combine them appropriately to to obtain the equivalent resistance through those sections Continue this process alternating between sections in series and sections in parallel until all the resistors have been combined to make a single equivalent resistor for the system Hint 2 Combining the resistors in the middle section After the current flows through the resistor in the water bath it splits into three separate paths each with two resistors What is the equivalent resistance texttipRrm middleRmiddle through this section Express your answer in ohms using three significant figures Hint 1 Series or parallel 39 M middle section there are six resistors How are they combined in the circuit H Typesettlng math 49 110f13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl ANSWER All six resistors are in series All six resistors are in parallel There are three paths in series and each path consists of two resistors in parallel There are three paths in parallel and each path consists of two resistors in series Hint 2 Resistance in each path Calculate the resistance of each path texttipRrm 1R1 texttipRrm 2R2 texttipRrm 3R3 from top to bottom respectively Express your answers separated by commas using three significant figures ANSWER texttipRrm 1R1 texttipRrm 2R2 texttipRrm 3R3 2oo2oo1oo Omega Hint 3 Resistors in parallel For resistors connected in parallel argefrac1Rrm totfrac1Rrm afrac1Rrm bcdots for any number of resistors Once the three separate paths in the middle section have been reduced to their equivalent resistances it is evident that the three paths are in parallel ANSWER texttipRrm middleRmiddIe 500 Omega Hint 3 Combining the rest of the resistors Now that the resistance for the middle section has been calculated you can replace the entire middle section with a single resistor of the calculated resistance You should draw the circuit again using this equivalent middlesection resistor When you do this you will see that the the circuit comprising the initial middle and final sections of resistors not counting the battery is now reduced to three equivalent resistors connected in series ANSWER texttipRrmtotaRtota 300 Omega Hint 3 Calculate the current in the equivalent resistor Calculate the current texttiprm batbat that flows through the battery and the equivalent resistor Express your answer in amperes using three significant figures ANSWER Typesetting math 49 12 of13 3222016 537 PM Weekly Assignment 03 https sessionmasteringphysics commyct as signmentPrintVieWdispl texttiprm batbat 100 rmA Hint 4 Calculate the current through the resistor in the water bath Calculate the current texttipl that flows through the resistor in the water bath Express your answer using three significant figures Hint 1 Current in the circuit Note that the first resistor is connected in series with the battery This means that the current flowing through the battery must flow into and out of the first resistor before splitting up in the middle section ANSWER texttip 100 rmA Hint 5 Calculate the power output of the resistor Calculate the power texttipPP dissipated in the resistor immersed in the water bath Express your answer in watts using three significant figures ANSWER texttipPP 200 rmW Hint 6 Heating the water Recall that for an object of mass m one has the relation QmcDeIta T where texttipDeta TDeltaT is the temperature change of the object texttipcc is the heat capacity of the object and texttipQQ is the heat or energy added to the object to change the temperature For our system the total heat delivered to the water bath is given by QPt where texttipPP is the energy per unit time power dissipated in the resistor and texttiptt is the time interval during which current flows through the circuit ANSWER texttiptt 1060 rms Correct Score Summary Your score on this assignment is 826 You received 992 out of a possible total of 12 points Typesetting math 49 13 of13 3222016 537 PM Weekly Assignment 05 https sessionmasteringphysics commyct as signmentPrintVieWdispl Weekly Assignment 05 Due 900pm on Monday February 22 2016 To understand how points are awarded read the Grading Policy for this assignment Problem 2212 A particle with a charge of 15 rm mu C experiences a force of 21 X10quot4 rm N when it moves at right angles to a magnetic field with a speed of 28 rm ms Part A What force does this particle experience when it moves with a speed of 62 rm ms at an angle of 27 rm quotcirc relative to the magnetic field Express your answer using two significant figures ANSWER F 21gtlt1O395 rmN Correct Problem 2214 An electron moving with a speed of 51 X105 rm ms in the positive x direction experiences zero magnetic force When it moves in the positive y direction it experiences a force of 19gtlt1O3913 rm N that points in the negative 2 direction Part A Find the components of the magnetic field Express your answer using two significant figures Enter your answers numerically separated by commas ANSWER Bx By Bz 23oo rmT Correct Charged Particles Moving in a Magnetic Field Ranking Task Five equalmass particles A E enter a region of uniform magnetic field directed into the page They follow the trajectories illustrated in the figure 10f8 3222016 550 PM Weekly Assignment 05 https sessionmasteringphysics commyct as signmentPrintVieWdispl Part A Which particle if any is neutral Hint 1 Neutral particles Since the magnitude of the magnetic force acting on a particle is given by F qusintheta a neutral particle with q 0 will not experience a magnetic force ANSWER particle A particle B particle C particle D particle E none Correct Part B Which particle if any is negatively charged Hint 1 Find the direction of the magnetic force The direction of the magnetic force is determined by the righthand rule With the given directions for velocity and magnetic field what is the direction of the magnetic force on a positively charged particle ANSWER left right ANSWER ll Typesetting math 4 2 of8 3222016 550 PM Weekly Assignment 05 https sessionmasteringphysics commyct as signmentPrintVieWdispl particle A particle B particle C particle D particle E none Correct Part C Rank the particles on the basis of their speed Rank from largest to smallest To rank items as equivalent overlap them Hint 1 Determining velocity based on particle trajectories A charged particle moving in a uniform magnetic field follows a circular trajectory By Newton39s second law the magnetic force acting on the particle must be equal to the product of its mass and acceleration qurm sintheta ma In our scenario the velocity and field vectors are perpendicular so theta 90rm degrees Also since the particle moves along a circular path the acceleration must equal the expression for centripetal acceleration argequ mfracvquot2r This can be solved for velocity to yield argev fracqBrm Thus the speed of a particle can be determined by measuring the radius of its circular path in a known magnetic field assuming that you also know the charge and mass of the particle ANSWER Correct Part D Rank the particles A B C and E on the basis of their speed Rank from largest to smallest To rank items as equivalent overlap them ANSWER Correct l Typesetting math 4 l 3 of8 3222016 550 PM Weekly Assignment 05 https sessionmasteringphysics commyct as signmentPrintVieWdispl Part E Now assume that particles A B C and E all have the same magnitude of electric charge Rank the particles A B C and E on the basis of their speed Rank from largest to smallest To rank items as equivalent overlap them Hint 1 Charged particle trajectories in magnetic fields Particles A B C and E are charged A charged particle moving in a uniform magnetic field follows a circular trajectory The speed of the particle has two distinct effects on the radius of its circular path First the faster the particle moves the larger the magnetic force acting on it by F qurm sintheta However the faster it moves the larger its centripetal acceleration by largearm centripetal fracvquot2r and therefore the larger the force needed to keep it in its circular path ANSWER Correct Mass Spectrometer J J Thomson is best known for his discoveries about the nature of cathode rays His other important contribution was the invention together with one of his students of the mass spectrometer a device that measures the ratio of mass texttipmm to positive charge texttipqq of an ion The spectrometer consists of two regions as shown in the figure In the first region an electric field accelerates the ion and in the second the ion follows a circular arc in a magnetic field The radius of curvature of the arc can be measured and then the mq ratio can be found I I fquot I H H 39 I ii I i I I I ll I I I Part A After being accelerated to a speed of 146x105 rm ms the particle enters a uniform magnetic field of strength 0800 rm T and travels in a circle of radius 320 rm cm determined by observing where it hits the screen as shown in the figure The results of this experiment allow one to find mq ll Typesetting math 4 4 of8 3222016 550 PM Weekly Assignment 05 Find the ratio mq for this particle Express your answer numerically in kilograms per coulomb Hint 1 Newton39s 2nd law and centripetal acceleration Recall that the expression for the force texttipFrm cFc acting on a particle of mass texttipmm traveling with speed v along a circle of radius R is argeF macfracmvquot2R https sessionmasteringphysics commyct as signmentPrintVieW displ Setting this expression equal to the general expression for the magnetic force acting on a moving particle will yield an equation from which you can find the required quantity Hint 2 Expression for the magnetic force When the velocity of the moving particle and the magnetic field are perpendicular to each other the magnetic force acting on the particle can be found from Fmqu where texttipqq is the charge of the particle texttipvv is its velocity and texttipBB is the magnitude of the magnetic field ANSWER mq 175gtlt10 6 rm kgC All attempts used correct answer displayed By sending the ions of various elements through a mass spectrometer Thomson39s student Francis Aston discovered that some elements actually contained atoms with several different masses The existence of atoms of the same element with different masses called isotopes can only be explained by the existence of a third subatomic particle in addition to protons and electrons the neutron Problem 2224 An electron accelerated from rest through a voltage of 550 rm V enters a region of constant magnetic field Part A If the electron follows a circular path with a radius of 18 rm cm what is the magnitude of the magnetic field Express your answer using two significant figures ANSWER B 44gtlt1O394 rmT Correct Problem 2222 in the fi ure is desi ned to allow char ed ll TYPesettmg math 4 9 g g 50f8 l 3222016 550 PM Weekly Assignment 05 particles with a speed of 4100 rm ms to pass through undeflected The magnetic field has a magnitude of 099 rm T Part A Find the magnitude of the required electric field Express your answer using two significant figures ANSWER E 4100 rm NC Correct Part B Find the direction of the required electric field ANSWER positive texttipxx direction negative texttipxx direction positive texttipyy direction negative texttipyy direction positive texttipzz direction negative texttipzz direction Correct https sessionmasteringphysics commyct as signmentPrintVieW displ Problem 2233 A 049 rm m copper rod with a mass of 018 rm kg carries a current of 11 rm A in the positive X direction Let upward be the positive ydirection Part A What is the magnitude of the minimum magnetic field needed to levitate the rod Express your answer using two significant figures A kl llln Typesetting math 41 6of8 3222016 550 PM Weekly Assignment 05 https sessionmasteringphysics commyct as signmentPrintVieWdispl B 033 rm T Correct Part B What is the direction of the minimum magnetic field needed to levitate the rod ANSWER positive texttipxx direction negative texttipxx direction positive texttipyy direction negative texttipyy direction positive texttipzz direction negative texttipzz direction Correct Problem 2268 Consider a current loop immersed in a magnetic field as in the figure It is given that 038 rm T and 95 rm A In addition the loop is a square 030 E quot l rm m on a side I Part A Find the magnitude of the magnetic force exerted on each side of the loop Express your answers using two significant figures separated by commas ANSWER N Typesetting math 4 7 of8 3222016 550 PM Weekly Assignment 05 https sessionmasteringphysics commyct as signmentPrintVieWdispl Frm top Frm bottom Frm left Frm right 001111 rm N Correct Problem 2242 Consider a current loop in a region of uniform magnetic field as shown in the figure a m P 39lH mi 139 Lquot Part A It is given that texttipBB 033 rm T and texttipll 95 rm A In addition the loop is a square 047 rm m on a side Find the magnitude of the torque exerted on the loop about the vertical axis of rotation using the data given Express your answer using two significant figures ANSWER tau 069 rm N cdot rm m Correct Score Summary Your score on this assignment is 890 You received 89 out of a possible total of 10 points Typesetting math 4 8 of8 3222016 550 PM Weekly Assignment 06 https sessionmasteringphysics commyct as signmentPrintVieWdispl Weekly Assignment 06 Due 900pm on Monday February 29 2016 To understand how points are awarded read the Grading Policy for this assignment Magnetic Field due to a Wire Conceptual Question The same amount of current is flowing through two wires labeled 1 and 2 in the figure in the directions indicated by the arrows In this problem you will determine the direction of the net magnetic field at each of the indicated points A C Win 2 Wire 1 Part A What is the direction of the magnetic field at point A Recall that the currents in the two wires have equal magnitudes Hint 1 The magnitude of the magnetic field due to a long straight currentcarrying wire The magnitude of a magnetic field is directly proportional to the amount of current flowing in the wire and inversely proportional to the distance from the wire Hint 2 The direction of the magnetic field due to a long straight currentcarrying wire The magnetic field surrounding a long straight wire encircles the wire as shown in the figure Electric current r Magnetic field 1 of8 3222016 605 PM Weekly Assignment 06 https sessionmasteringphysics commyct as signmentPrintVieWdispl The direction of the field is determined by a righthand rule Grasp the wire with the thumb of your right hand in the direction of the current flow The direction in which your fingers encircle the wire is the direction in which the magnetic field encircles the wire Hint 3 How to approach the problem To determine the direction of the magnetic field at point A you must determine the contribution to the field from both of the wires The field at point A is the vector sum of these two contributions Because point A is in the same plane as the wires the contribution to the net magnetic field at point A from wire 1 or wire 2 will either point into or out of the screen Keep in mind that if the magnetic fields are in opposite directions the larger field will decide the direction of the net magnetic field If they are the same size the net magnetic field will be zero Hint 4 Find the direction of the magnetic field at point A due to wire 1 Is the magnetic field from wire 1 directed into or out of the screen at point A Be sure to point your thumb in the direction of the current in this case to the right ANSWER out Hint 5 Find the direction of the magnetic field at point A due to wire 2 Is the magnetic field from wire 2 directed into or out of the screen at point A Be sure to point your thumb in the direction of the current in this case downward ANSWER out ANSWER points out of the screen at A points into the screen at A points neither out of nor into the screen and at A at A Correct Part B What is the direction of the magnetic field at point B Hint 1 Find the direction of the magnetic field at point B due to wire 1 2 of8 3222016 605 PM Weekly Assignment 06 3of8 Is the magnetic field from wire 1 directed into or out of the screen at point B ANSWER out Hint 2 Find the direction of the magnetic field at point B due to wire 2 Is the magnetic field from wire 2 directed into or out of the screen at point B ANSWER out ANSWER points out of the screen at B points into the screen at B points neither out of nor into the screen and at B at B Correct Part C What is the direction of the magnetic field at point C Hint 1 Find the direction of the magnetic field at point C due to wire 1 Is the magnetic field from wire 1 directed into or out of the screen at point C ANSWER out Hint 2 Find the direction of the magnetic field at point C due to wire 2 Is the magnetic field from wire 2 directed into or out of the screen at point C ANSWER https sessionmasteringphysics commyct as signmentPrintVieW displ 3222016 605 PM Weekly Assignment 06 https sessionmasteringphysics commyct as signmentPrintVieWdispl out ANSWER points out of the screen at C points into the screen at C points neither out of nor into the screen and at C at C Correct Problem 2246 A long straight wire carries a current of 76 Part A How far from this wire is the magnetic field it produces equal to the Earth39s magnetic field which is approximately Express your answer using two significant figures ANSWER 30 Correct Problem 2290 A powerful bolt of lightning can carry a current of 230 Part A Treating a lightning bolt as a long thin wire calculate the magnitude of the magnetic field produced by such a bolt of lightning at a distance of 36 Express your answer using two significant figures ANSWER 13 4 of8 3222016 605 PM Weekly Assignment 06 https sessionmasteringphysics commyct as signmentPrintVieWdispl Correct Part B If two such bolts strike simultaneously at a distance of 36 from each other what is the magnetic force per meter exerted by one bolt on the other Express your answer using two significant figures ANSWER 029 All attempts used correct answer displayed Problem 2297 Solenoids produce magnetic fields that are relatively intense for the amount of current they carry To make a direct comparison consider a solenoid with 56 turns per centimeter a radius of 125 and a current of 0654 Part A Find the magnetic field at the center of the solenoid Express your answer using two significant figures ANSWER 46 All attempts used correct answer displayed Part B What current must a long straight wire carry to have the same magnetic field as that found in part A Let the distance from the wire be the same as the radius of the solenoid 125 Express your answer using two significant figures ANSWER 290 Correct Problem 236 5 of8 3222016 605 PM Weekly Assignment 06 https sessionmasteringphysics commyctassignmentPrintVieWdisp1 At a certain location the Earth39s magnetic field has a magnitude of 61gtlt1O395 and points in a direction that is 75 below the horizontal Part A Find the magnitude of the magnetic flux through the top of a desk at this location that measures 140 by 73 Express your answer using two significant figures ANSWER 6Ogtlt1O395 Correct Problem 239 A 048 magnetic field is perpendicular to a circular loop of wire with 56 turns and a radius of 14 Part A If the magnetic field is reduced to zero in 010 what is the magnitude of the induced emf Express your answer using two significant figures ANSWER 17 All attempts used correct answer displayed Problem 2311 rill fM E1 1 Iii 1 l H l l l l i l I r l 5quot l i l l 111 i112 l3939la its luri ujrquot 113 rtl l i it The figure 4 shows the magnetic flux through a singleloop coil as a function of time Part A What is the induced emf in the coil at 6 of8 3222016 605 PM Weekly Assignment 06 https sessionmasteringphysics commyct as signmentPrintVieWdispl ANSWER 100 Correct Part B What is the induced emf in the coil at ANSWER Correct Part C What is the induced emf in the coil at ANSWER 375 All attempts used correct answer displayed Problem 2316 A single conducting loop of wire has an area of 79gtlt1O 2 and a resistance of 120 Perpendicular to the plane of the loop is a magnetic field of strength 037 Part A At what rate in must this field change ifthe induced current in the loop is to be 030 Express your answer using two significant figures ANSWER 460 Correct Understanding Changing Flux 7 of8 3222016 605 PM Weekly Assignment 06 https sessionmasteringphysics commyct as signmentPrintVieWdispl In this problem you will use Lenz39s law to explore what happens when an electromagnet is activated a short distance from a wire loop You will need to use the righthand rule to find the direction of the induced current Consider the arrangement shown in Part A When the switch is open which of the following statements about the magnetic flux through the wire loop is true Assume that the direction of the vector area of the wire loop is to the right ANSWER There is no magnetic flux through the wire loop There is a positive flux through the wire loop 8 of8 3222016 605 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl Weekly Assignment 07 Due 900pm on Monday March 7 2016 To understand how points are awarded read the Grading Policy for this assignment Induced Current in a Pair of Solenoids Conceptual Question For each of the actions depicted determine the direction right left or zero of the current induced to flow through the resistor in the circuit containing the secondary coil The coils are wrapped around a plastic core Part A Immediately after the switch is closed as shown in the figure in which direction does the current flow through the resistor 2f ulnar witch Hint 1 Magnetic flux Magnetic flux is the product of the component of magnetic field perpendicular to a given area and the area itself Conceptually it is proportional to the number of magnetic field lines passing through a given area Hint 2 Electromagnetic induction Whenever magnetic flux through an area changes an electromotive force emf is created around the area This induced emf has a direction such that if a conductor is present current will flow to create a secondary magnetic field that opposes the change in the original magnetic flux Basically the induced current will quottryquot to maintain the initial value of the magnetic flux Hint 3 Magnetic field produced by a coil The magnetic field produced by a coil has the same directional properties as the field produced by a single loop To determine the direction of the magnetic field produced by a current in a coil use the righthand rule for magnetic fields Curl the finger of your right hand in the direction of the current flowing through the loop your thumb now points in the direction of the magnetic field produced by the coil Hint 4 Find the direction of the magnetic field through the secondary coil Initially there is no magnetic field through the secondary coil the coil connect to the resistor After the switch is closed current flows through the primary coil and a magnetic field is produced through both coils Does the magnetic field that passes through the secondary coil point to the right or to the left ANSWER right left Hint 5 Induced magnetic field Since the magnetic field in the secondary coil changed from zero to a leftwarddirected field when the switch was closed the magnetic flux through the secondary coil has increased Thus current will flow in the secondary coil to create a magnetic field oriented to the right to oppose this increase in flux Therefore you need to determine the direction in which current must flow through the secondary coil and thus the resistor to create a field through the secondary coil directed to the right Use the righthand rule for magnetic fields to find the direction of this current ANSWER l Typesetting math 68 1 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl right left Z9 I39O Correct Part B If the switch is then opened as shown in the figure in which direction does the current flow through the resistor open Switch Hint 1 Find the direction of the magnetic field through the secondary coil before the switch is opened Before the switch is opened does the magnetic field that passes through the secondary coil point to the right or to the left Hint 1 Righthand rule for magnetic fields To find the direction of the magnetic field produced by a current flowing through a loop curl the finger of your right hand in the direction of the current in the loop Your thumb will point in the direction of the magnetic field produced by the coil ANSWER right left Hint 2 Induced magnetic field Since the magnetic field in the secondary coil changed from a leftwarddirected field to zero when the switch was opened the magnetic flux through the secondary coil had decreased Thus current will flow in the secondary loop to create a magnetic field oriented to the left to replace this decrease in flux Therefore you need to determine the direction in which current must flow through the secondary coil and thus the resistor to create a field directed to the left Use the righthand rule for magnetic fields to find the direction of this current ANSWER right left Z9 I39O Correct Part C Immediately after the switch is closed as shown in the figure in which direction does the gh the resistor aLLlamvJ39EIJLLLI IQJAJ Typesetting math 68 2 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl close HRH39lll l39l ANSWER right left zero Correct In Part D the left coil only is moving to the left with velocity 3917 Part D If the circuit containing the battery moves to the left as shown in the figure in which direction does the current flow through the resistor I cci trimcs left Hint 1 Find how the magnetic flux through the secondary changes If the primary coil the coil connected to the battery moves to the left how does the magnetic flux through the secondary coil change ANSWER It decreases It increases It remains constant Hint 2 Induced magnetic field Since the magnetic field in the secondary coil became weaker when the source of the field the primary coil moved away the magnetic flux through the secondary coil has decreased Thus current will flow in the secondary loop to create a magnetic field oriented in the same direction to the left as the original field to replace this decrease in flux Therefore you need to determine the direction in which current must flow through the secondary coil and thus the resistor to create a field to the left Use the righthand rule for magnetic fields to find the direction of this current ANSWER l Typesetting math 68 3 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl right left Z9 I39O Correct Conceptual Exercise 2313 The figure shows four different situations in which a metal ring moves to the right with constant speed through a region with a varying magnetic field The intensity of the color indicates the intensity of the field and in each case the field either increases or decreases at a uniform rate from the left edge of the colored region to the right edge The direction of the field in each region is indicated Part A For the first case state whether the induced emf is clockwise counterclockwise or zero ANSWER clockwise counterclockwise Z9 I39O Correct Part B For the second case state whether the induced emf is clockwise counterclockwise or zero ANSWER clockwise counterclockwise Z9 I39O Correct Part C For the third case state whether the induced emf is clockwise counterclockwise or zero ANSWER I Typesetting math 68 4 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl clockwise counterclockwise Z9 I39O Correct Part D For the fourth state whether the induced emf is clockwise counterclockwise or zero ANSWER clockwise counterclockwise Z9 I39O Correct Conceptual Induction A loop of wire is initially held above a short solenoid A constant counterclockwise as viewed from above current I passes through the turns of the solenoid The loop of wire is steadily lowered eventually quotencirclingquot the solenoid Throughout this problem when you answer questions about the direction of current assume that you are viewing the wire loop from above looking downward Part A What is the direction of the induced current in the loop when the loop is above the solenoid moving downward Hint 1 Using Lenz39s law The current in the solenoid generates a magnetic field and therefore a magnetic flux passing through the loop As the wire loop approaches the solenoid the flux increases A current is induced in the loop According to Lenz39s law the flux produced by the induced current must oppose the change in flux due to the solenoid39s magnetic field Hint 2 Using Faraday39s law You can also think about this problem in terms of Faraday39s law According to this law the induced emf 5 that produces current in the loop of area A is given by 5 where q 2 BA cos 6 is the magnetic flux through the loop created by a magnetic field of magnitude B oriented at an angle of 0 relative to the loop Note that in this problem 0 180 degrees so i 2 BA If the magnetic flux is increasing then the emf is such that it produces the current whose induced magnetic field is in the opposite direction to that of If the magnetic flux is decreasing then the induced field is in the direction of ANSWER Typesetting math 68 5 of 17 3222016 634 PM Weekly Assignment 07 60f17 clockwise counterclockwise no current Correct Part B What is the direction of the induced current at the instant that the loop is at the midpoint of the solenoid and still moving downward Hint 1 Applying Lenz39s law https sessionmasteringphysics commyct as signmentPrintVieW displ As the loop approaches the solenoid from above the number of magnetic field lines passing through the loop due to the magnetic field of the solenoid increases The number of magnetic field lines passing through the loop represents the magnitude of the magnetic flux through the loop The number of magnetic field lines passing through the loop continues to increase until the loop arrives at the midpoint of the solenoid Once the loop travels beyond the solenoid39s midpoint the number of magnetic field lines passing through the loop begins to decrease Therefore when the loop is exactly at the midpoint of the solenoid the number of magnetic field lines passing through the loop must be neither increasing nor decreasing At the instant the wire loop is at the midpoint of the solenoid there is no change in magnetic flux through the loop ANSWER clockwise counterclockwise no current Correct Part C What is the direction of the induced current when the loop is below the solenoid and moving downward ANSWER clockwise counterclockwise no current Correct Faraday39s Law and Induced Emf Learning Goal To understand the terms in Faraday39s law and to be able to identify the magnitude and direction of induced emf Faraday39s law states that induced emf is directly proportional to the time rate of change of magnetic flux Mathematically it can be written as A I B 8 At where 5 is the emf induced in a closed loop and AltIgtB At is the rate of change of the magnetic flux through a surface bounded by the loop For uniform magnetic fields the magnetic flux is given by B B A BA cos0 where 0 is the angle between the magnetic field E and the normal to the surface of area A To find the direction of the induced emf one can use Lenz39s law 39quotTyp se39mng quotlath 68 magnetic eld opposes the change in the magnetic flux that induced the current 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl For example if the magnetic flux through a loop increases the induced magnetic field is directed opposite to the quotparentquot magnetic field thus countering the increase in flux If the flux decreases the induced current39s magnetic field has the same direction as the parent magnetic field thus countering the decrease in flux Recall that to relate the direction of the electric current and its magnetic field you can use the righthand rule When the fingers on your right hand are curled in the direction of the current in a loop your thumb gives the direction of the magnetic field generated by this current Cm In this problem we will consider a rectangular loop of wire with sides a and y placed in a region where a uniform magnetic field exists as shown in The resistance ofthe loop is R For the purposes ofthis problem we will assume that the area vectorA 39 f f f f 39j 39 3 f pointsoutonhepage r er 1 1 Initially the field is perpendicular to the plane of the loop and is directed out of the page The loop V I r can rotate about eitherthe vertical or horizontal axis passing through the midpoints of the opposite I i J I I i sides as shown rquot 1 l 3 ill I I l l Ii 3 is 39quot 39 vli I i l I1 l I I I l1 i E i Ia i39i liEi iii Q ll Ia I I a I Ila 9 II II I a Iquot i u I i ii is u I if i I l I o l I Q l l i iii 1 I I l D i l39 in i a i ii i s ill i Iquot l i riliiII I Eiill lial Part A Which of the following changes would induce an electromotive force emf in the loop When you consider each option assume that no other changes occur Check all that apply ANSWER The magnitude of B increases The magnitude of B decreases The loop rotates about the vertical axis vertical dotted line shown in the diagram The loop rotates about the horizontal axis horizontal dotted line shown in the diagram The loop moves to the right while remaining in the plane of the page The loop moves toward you out of the page while remaining parallel to itself Correct Part B Find the flux EB through the loop Express your answer in terms of as y and B ANSWER ltIgtB wyB Correct Part C If the magnetic field steadily decreases from B to zero during a time interval t what is the magnitude 8 of the induced emf Express your answer in terms of m y B and t Hint 1 Find the change in magnetic flux What is the total change in magnetic flux AQB during this time interval Typesetting math 68 lr answer in terms of m y and B 7 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl ANSWER AQB Bary ANSWER Correct Part D If the magnetic field steadily decreases from B to zero during a time interval t what is the magnitude I of the induced current Express your answer in terms of texttipxx texttipyy texttipBB texttiptt and the resistance texttipRR of the wire ANSWER texttipll argefracxyBRt Correct Part E If the magnetic field steadily decreases from texttipBB to zero during a time interval texttiptt what is the direction of the induced current ANSWER clockwise counterclockwise Correct The flux decreases so the induced magnetic field must be in the same direction as the original parent magnetic field Therefore the induced magnetic field is out of the page Using the righthand rule we deduce that the direction of the current is counterclockwise Part F Which of the following changes would result in a clockwise emf in the loop When you consider each option assume that no other changes occur Check all that apply ANSWER The magnitude of texttipvecBBvec increases The magnitude of texttipvecBBvec decreases The loop rotates through 45 degrees about the vertical axis vertical dotted line shown in the diagram The loop rotates through 45 degrees about the horizontal axis horizontal dotted line shown in the diagram The loop moves to the right while remaining in the plane of the page The loop moves toward you out of the page while remaining parallel to itself Correct Clockwise emf implies that the induced magnetic field is directed into the page Therefore the magnetic flux of the original field must be increasing Only the first option corresponds to increasing flux Typesetting math 68 l 8 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl Problem 2326 A loop of wire is dropped and allowed to fall between the poles of a horseshoe magnet as shown in the figure Part A State whether the induced current in the loop is clockwise or counterclockwise when the loop is above the magnet ANSWER clockwise counterclockwise Correct Part B State whether the induced current in the loop is clockwise or counterclockwise when the loop is below the magnet ANSWER clockwise counterclockwise Correct Magnetic Light Switch Ranking Task Six identical vertical metal bars start at the positions shown below and move at constant velocities through identical magnetic fields The bars make electrical contact with and move along frictionless metal rods attached to light bulbs Part A At the instant shown rank these six scenarios on the basis of the magnitude of the current in the light bulb Rank from largest to smallest To rank items as equivalent overlap them Hint 1 Faraday39s law of induction The magnitude of the current in the light bulb is proportional to the magnitude of the emf induced in each scenario The emf induced is equal to the time rate of change of the magnetic flux through the closed loop formed by the sliding bar Typesetting math 68 9 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl Hint 2 Change in magnetic flux Magnetic flux is the product of the magnetic field perpendicular to a given area and the area itself Since the magnetic field is constant in this case any change in flux must be due solely to a change in area Hint 3 Change in area The area of the closed loop formed by the sliding bar changes at a rate that is proportional to the velocity of the sliding bar ANSWER Correct Problem 2339 The figure shows a zeroresistance rod sliding to the right on two zeroresistance rails separated Y m in t E by the distance texttipLL 0445 rm m The rails are connected by a 128 rm Omega 3 45 le 3i 37 3 nil resistor and the entire system is in a uniform magnetic field with a magnitude of 0810 rm T l a 7 3 m A x w j if I I II I I ll I a Ij Part A Find the force that must be exerted on the rod to maintain a constant current of 0155 rm A in the resistor ANSWER F 559 rm mN Correct l Typesetting math 68 10 of 17 3222016 634 PM Weekly Assignment 07 What is the rate of energy dissipation in the resistor ANSWER Prm dissipation 0308 rmW Correct Part C What is the mechanical power delivered to the rod ANSWER Prm mechanical 0308 rmW Correct https sessionmasteringphysics commyct as signmentPrintVieW displ Problem 2341 The lightbulb in the circuit shown in the figure has a resistance of 12 rm Omega and consumes 96 rm W of power the rod is 118 rm m long and moves to the left with a constant speed The V l strength of the magnetic field is 25 rm T E 39 n dhx i 39i39l39lJi l 2 car ml r i El lunamzmrifr l a l aquot l Part A Find the current in the circuit Express your answer using two significant figures ANSWER 089 rm A Correct Part B Find the speed of the rod Express your answer using two significant figures ANSWER v 36 rm ms Correct Problem 262 F39Typesg in 39math 6 is of two mirrors form a vertex with an angle of 115 rm l circ 11 of 17 3222016 634 PM Weekly Assignment 07 Part A If a ray of light strikes mirror 1 with an angle of incidence of 50 rm l circ find the angle of reflection of the ray when it leaves mirror 2 Express your answer using two significant figures ANSWER theta 65 l circ Correct https sessionmasteringphysics commyct as signmentPrintVieW displ Problem 2610 A 130foot long nearsighted python is stretched out perpendicular to a plane mirror admiring its reflected image Part A If the greatest distance to which the snake can see clearly is 260 rm ft how close must its head be to the mirror for it to see a clear image of its tail ANSWER d 650 rm ft Correct Problem 2628 An object with a height of 49 rm cm is placed 23 rm m in front of a concave mirror with a focal length of 058 rm m Part A Determine the approximate location of the image using a ray diagram Express your answer using two significant figures ANSWER drm i 078 rm m in front of the mirror Correct Part B Determine the approximate size of the image using a ray diagram Express your answer using two significant figures ANSWER hrm i 17 rm cm Correct Part C Is the image upright or inverted ANSWER l Typesetting math 68 12 0f17 3222016 634 PM Weekly Assignment 07 upnght inverted Correct https sessionmasteringphysics commyct as signmentPrintVieW displ Problem 2629 An object with a height of 38 rm rm cm is placed 25 rm rm m in front of a concave mirror with a focal length of 050 rm rm m Part A Find the location of the image produced by the mirror using the mirror and magnification equations Express your answer using two significant figures ANSWER drm i 063 rm m Correct Part B Find the magnification of the image produced by the mirror using the mirror and magnification equations Express your answer using two significant figures ANSWER m O25 Correct Problem 2630 An object with a height of 49 rm cm is placed 23 rm m in front of a convex mirror with a focal length of O55 rm m Part A Determine the approximate location of the image using a ray diagram Express your answer using two significant figures ANSWER di 044 rm m behind the mirror Correct Part B Determine the approximate size of the image using a ray diagram Express your answer using two significant figures ANSWER hi 95 rm cm i Typesetting math68 13 0f17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl Correct Part C Is the image upright or inverted ANSWER upnght inverted Correct Problem 2633 IF A magician wishes to create the illusion of a 257rm mta elephant He plans to do this by forming a virtual image of a 550rm cmta model elephant with the help of a spherical mirror Part A Should the mirror be concave or convex ANSWER concave convex Correct Part B If the model must be placed 325 rm rm m from the mirror what radius of curvature is needed ANSWER R 827 rm m All attempts used correct answer displayed Part C How far from the mirror will the image be formed ANSWER drm i 152 rm m Correct Problem 2631 An object with a height of 42 rm rm cm is placed 21 rm rm m in front of a convex mirror with a focal length of 040 rm rm m Part A l Typesetting math 68 lof the image produced by the mirror using the mirror and magnification equations 14 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdisp1 Express your answer using two significant figures ANSWER drm i O34 rm m Correct Part B ANSWER in front of the mirror behind the mirror Correct Part C Find the magnification of the image produced by the mirror using the mirror and magnification equations Express your answer using two significant figures ANSWER m 016 Correct Problem 2634 A person 18 rm m tall stands 076 rm m from a reflecting globe in a garden Part A If the diameter of the globe is 18 rm cm where is the image of the person relative to the surface of the globe Express your answer using two significant figures ANSWER di 42 rm cm behind the surface of the globe Correct Part B How large is the person39s image Express your answer using two significant figures ANSWER hi 10 rm cm Correct l Typesetting math 68 15 of 17 3222016 634 PM Weekly Assignment 07 https sessionmasteringphysics commyct as signmentPrintVieWdispl Problem 2637 A concave mirror produces a virtual image that is three times as tall as the object Part A If the object is 24 rm rm cm in front of the mirror what is the image distance Express your answer using two significant figures ANSWER drm i 72 rm cm Correct Part B What is the focal length of this mirror Express your answer using two significant figures ANSWER f 36 rm cm Correct Problem 2638 A concave mirror produces a real image that is three times as large as the object Part A If the object is 27 rm cm in front of the mirror what is the image distance Express your answer using two significant figures ANSWER di 81 rm cm Correct Part B What is the focal length of this mirror Express your answer using two significant figures ANSWER f 20 rm cm Correct Problem 2639 The virtual image produced by a convex mirror is onequarter the size of the object l Typesetting math68 l 16 of17 3222016 634 PM Weekly Assignment 07 Part A If the object is 30 rm rm cm in front of the mirror what is the image distance Express your answer using two significant figures ANSWER drm i 75 rm cm Correct Part B What is the focal length of this mirror Express your answer using two significant figures ANSWER f 1O rmcm Correct https sessionmasteringphysics commyct as signmentPrintVieW displ Problem 2641 You view a nearby tree in a concave mirror The inverted image of the tree is 30 rm rm cm high and is located 80 rm rm cm in front of the mirror Part A If the tree is 20 rm rm m from the mirror what is its height Express your answer using two significant figures ANSWER hrm 0 75 rm m Correct Score Summary Your score on this assignment is 947 You received 2083 out of a possible total of 22 points i Typesetting math 68 17 of17 3222016 634 PM Weekly Assignment 04 included in Exam 1 but Kirchhoff s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 Weekly Assignment 04 included in Exam 1 but Kirchhoff39s Rules will be included in Exam 2 Due 900pm on Monday February 15 2016 To understand how points are awarded read the Grading Policy for this assignment Brightness of Light Bulbs Ranking Task 1 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 Part A Consider a circuit containing five identical light bulbs and an ideal battery Assume that the resistance of each light bulb remains constant Rank the bulbs A through E based on their brightness Rank from brightest to dimmest To rank items as equivalent overlap them Hint 1 How to approach the problem The greater the current in a bulb the brighter the bulb is Compare the currents in the light bulbs Hint 2 Comparing bulb A to bulb B When a wire quotsplitsquot the current splits according to the resistance in each pathway How does the resistance in the pathway through bulb A compare to the resistance in the pathway through bulb B Hint 3 Comparing bulb D to bulb E Bulb D and bulb E are connected in series How much of the charge that goes through D also goes through E Hint 4 Comparing bulb C to bulb D or E When a wire quotsplitsquot the current splits according to the resistance in each pathway How does the resistance in the pathway of bulb C compare to the resistance in the pathway of bulbs D and E Recall that two bulbs connected in series have more resistance than a single bulb Hint 5 Comparing bulb C to bulb A or B What fraction of the total current through the battery goes through the pathway containing bulb A Recall that the pathways through bulbs A and B have the same resistance since the bulbs are identical Compare that number to the fraction of the current that goes through the pathway containing bulb C ANSWER Correct Now consider what happens when a switch in the circuit is opened 2 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 j39p l39l Switch Part B What happens to the brightness of bulb A Hint 1 How to approach this part Light bulbs D and E are in effect disconnected from the circuit The current exists only in light bulbs A B and C How would the change affect the currents in A B and C Hint 2 Consider changes in resistance How does the resistance of bulb C alone compare with the resistance of bulb C in parallel with bulbs D and E ANSWER It gets dimmer It gets brighter There is no change Correct Part C What happens to bulb C Hint 1 How to approach this part This question can be answered by calculating the quotbeforequot and quotafterquot currents through C in terms of the emf provided by the battery and the resistance of each bulb Hint 2 Find the current in bulb C earlier Before the switch was open the total resistance of the earlier circuit was 7 6R where R is the resistance of one bulb What was the current IC in bulb C Let the emf produced by the battery be V Express your answer in terms of V and R ANSWER Hint 3 Find the current in bulb C now What is the current Iqafter through bulb C after opening the switch Let the emf produced by the battery be V Express your answer in terms of V and R ANSWER 3 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdispl 2 ICafter ANSWER It gets dimmer It gets brighter There is no change Correct This is why appliances in your home are always connected in parallel with the voltage source Otherwise turning some of them on or off would cause the current in others to change which could damage them Problem 2161 Consider the circuit shown in the figure Suppose the four resistors in this circuit have the values R1 12 Q R2 74 Q R3 699 and R4 13 Q and thatthe emfofthe battery isS 15 V Part A Find the current through each resistor using the rules for series and parallel resistors Express your answers using two significant figures separated by commas ANSWER I1 I2I3 I4 O87022065022 A All attempts used correct answer displayed Part B Find the current through each resistor using Kirchhoff39s rules Express your answers using two significant figures separated by commas ANSWER 1112I3I4 O87022065022 A Correct i A Simple Network of Capacitors 40f16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 In the figure are shown three capacitors with capacitances TE 0391 2 600 uF Cg 300 uF 0393 2 500 uF The capacitor network is connected to an u applied potential V111 After the charges on the capacitors have reached their final values the till charge Q2 on the second capacitor is 400 uC r it P 2 ll Part A What is the charge Q1 on capacitor 01 Hint 1 How to approach the problem Consider only the initial section of the network from a to 3 Develop a relation between the capacitance and charge for each capacitor in that section Use the capacitances 0391 and 02 and the final charge Q2 on 0392 to calculate the charge Q1 on 01 Hint 2 Series or parallel Are capacitors Cl and 02 connected in series or in parallel ANSWER senes parallel Hint 3 Calculate the potential difference across the second capacitor Calculate the potential difference V2 across the second capacitor Express your answer in volts to three significant figures Hint 1 Equation for capacitance Recall that for any capacitor one has the relation 0 where Q is the charge on each plate of the capacitor and V is the potential difference across the capacitor not the difference across the whole network ANSWER V2 133 V Hint 4 Calculate the potential difference across the first capacitor V1 Calculate the potential difference V1 across the first capacitor Express your answer in volts to three significant figures Hint 1 Parallel capacitors and potential difference If two capacitors are connected in parallel how are the potential differences across each capacitor related Note that the left plate and right plate are connected to points a and C respectively for both capacitors ANSWER 5 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 V1 133 V ANSWER Q1 800 uC Correct Part B What is the charge on capacitor 03 Express your answer in microcoulombs to three significant figures Hint 1 How to approach the problem Determine whether the third capacitor 03 is connected in series or in parallel with the first section of the network from a to 3 Calculate the total charge of the initial section of the network Qad Use the result to find the charge on the third capacitor Q3 Hint 2 Series or parallel Is the third capacitor 03 connected in series or in parallel with the first section of the network from a to d ANSWER senes parallel Hint 3 Capacitors in series For capacitors connected in series the positive plate of one capacitor is connected to the negative plate of the other capacitor Since the charge on the two plates must come from separation of charges in the initially neutral plates charge is never created or destroyed the two plates must have charges of equal magnitude and opposite signs Therefore the charge must be the same for the two capacitors In this problem the network between a and d is in series with capacitor 03 Therefore the total charge on that network must equal the charge on C3 Hint 4 Calculate the total charge in the initial section Calculate Qad the total charge stored in the initial section Express your answer in microcoulombs to three significant figures Hint 1 How to find the charge in the initial section You already know the charge on the first two capacitors Q1 and Q2 in the initial section between points a and d The total charge must therefore be the sum of the charges in each capacitor ANSWER Qad 120 MC ANSWER Q3 120 uC Correct Part C 6 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b 70f16 https sessionmasteringphysics commyct as signmentPrintVieW displ What is the applied voltage V211 Express your answer in volts to three significant figures Hint 1 How to approach the problem Reduce the network of capacitors to a single equivalent capacitor connecting points a and b directly Determine the capacitance Cab and charge Qab on the equivalent capacitor Then calculate the total potential difference Vab Hint 2 Calculate the equivalent capacitance Calculate the equivalent capacitance Cab of the network Express your answer in microfarads to three significant figures Hint 1 Calculate the equivalent capacitance of the initial section Calculate the equivalent capacitance Cad of the capacitors in the initial section between points a and C Express your answer in microfarads to three significant figures Hint 1 Capacitance for capacitors in parallel The total capacitance for two capacitors with capacitances Ca and CB connected in parallel is given by Ctotal 2 Ca Cg ANSWER Cad 900 IMF Hint 2 Capacitance for capacitors in series 1 L i 0mm Ca 03 Remember to solve for Ctotal and not Its The total capacitance for two capacitors in series Ca and Cg is given by reciprocal ANSWER Cab 321 uF Hint 3 Find the total charge Find the total charge Qab stored in the equivalent capacitor Express your answer in microcoulombs to three significant figures Hint 1 Finding the charge of the equivalent capacitor Remember that since the section between points a and d and the section between points 3 and b are in series the charge on the equivalent capacitor will be the same as the charge stored in each section Using the value of Q3 for the third capacitor in the network as calculated in Part B you can show that Qab Qad de Q3 ANSWER 621 120 MC ANSWER V215 373 V Correct 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Problem 2169 An 12V battery is connected to three capacitors in series The capacitors have the following capacitances 45 uF 14 MF and 34 HF Part A Find the voltage across the 34 uF capacitor Express your answer using two significant figures ANSWER AV 11 V Correct Problem 2168 Part A Find the equivalent capacitance between points A and B for the group of capacitors shown in the figure Suppose 0114uF02 89 MP and 03 27 MP Express your answer using two significant figures Ci lil til A B I C Cr Il H I IF IT ANSWER Ceq 21 uF Correct Problem 2172 Terminals A and B in the figure are connected to a 12 V battery Consider Cl 16 uF 02 75 uFand0317uF Ci lll ill A E I c Ch II II IF IT 8 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdispl Part A Find the energy stored in each capacitor Express your answers using two significant figures separated by commas ANSWER U1U2U3 12026011 111 All attempts used correct answer displayed Charging a Capacitor in an RC Circuit Learning Goal To understand the dynamics of a series RC circuit Consider a series circuit containing a resistor of resistance R and a capacitor of capacitance 039 connected to a source of EMF 8 with negligible internal resistance The wires are also assumed to have zero resistance Initially the switch is open and the capacitor discharged Let us try to understand the processes that take place after the switch is closed The charge of the R capacitor the current in the circuit and correspondingly the voltages across the resistor and the capacitor will be changing Note that at any moment in time during the life of our circuit Kirchhoff39s A my loop rule holds and indeed it is helpful 8 VR V0 2 0 where VB is the voltage across the I E resistor and V0 is the voltage across the capacitor quot5quot Part A Immediately after the switch is closed what is the voltage across the capacitor ANSWER 5 1 E5 Z9 I39O Correct 9 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 Part B Immediately after the switch is closed what is the voltage across the resistor ANSWER 5 1 55 Z9 I39O Correct Part C Immediately after the switch is closed what is the direction of the current in the circuit ANSWER clockwise counterclockwise There is no current because the capacitor does not allow the current to pass through Correct Although no charge can physically pass through the gap between the capacitor plates it can flow in the rest of the circuit The current in the capacitor can be thought of as a different sort of current not involved with the flow of charge but with an electric field that is increasing with time This current is called the displacement current Of course when the charge of the capacitor is not changing then there is no current of any kind Part D After the switch is closed which plate of the capacitor eventually becomes positively charged ANSWER the top plate only the bottom plate only both plates neither plate because electrons are negatively charged Correct Part E Eventually the process approaches a steady state In that steady state the charge of the capacitor is not changing What is the current in the circuit in the steady state Hint 1 Charge and current If the charge of the capacitor is not changing then no charge can be flowing through the circuit ANSWER 10 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 ulm Correct Part F In the steady state what is the charge q of the capacitor Express your answer in terms of any or all of 8 R and C Hint 1 Voltage in the steady state If the current is zero the voltage across the resistor is zero Using Kirchhoff39s loop rule the magnitude of the voltage drop across the capacitor must therefore be 8 ANSWER q CE Correct Part G How much work W is done by the voltage source by the time the steady state is reached Express your answer in terms of any or all of 8 R and C Hint 1 Charge and EMF By definition the EMF of the source is defined as the ratio of the work done by the source quotpushingquot a charge q through the circuit and the magnitude of that charge 8 Wq Initially the capacitor was uncharged By the time steady state has been reached all of the charge that is on the capacitor q in this case has been pushed through the circuit ANSWER W 082 Correct Note that the work done depends on C39 but not on R This is because it is the capacitor that determines the amount of charge flow through the circuit Charge flow stops when 10 8 The resistance does however affect the rate of charge flow ie the current Of the total work done by the battery half is stored as electrostatic energy in the capacitor while the other half is dissipated as losses in the resistor The high loss percentage of this simple circuit is independent of the value of the resistance of the circuit Charged Capacitor and Resistor Learning Goal To study the behavior of a circuit containing a resistor and a charged capacitor when the capacitor begins to discharge A capacitor with capacitance C is initially charged with charge q At time t 0 a switch is thrown to close the circuit connecting the capacitor in series with a resistor of resistance R 11 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 1 i I r quotI Part A What happens to the charge on the capacitor immediately after the switch is thrown ANSWER The electrons on the negative plate of the capacitor are held inside the capacitor by the positive charge on the other plate Only the surface charge is held in the capacitor the charge inside the metal plates flows through the resistor The electrons on the negative plate immediately pass through the resistor and neutralize the charge on the positive plate The electrons on the negative plate eventually pass through the resistor and neutralize the charge on the positive plate Correct Part B What is the current I0 that flows through the resistor immediately after the switch is thrown Express your answer in terms of any or all of the quantities q R and C Hint 1 How to approach the problem Find the voltage across the resistor at t 0 Then use Ohm39s law to find the current I0 through the resistor Hint 2 Find the voltage att 0 What is the voltage VI across the capacitor at time t 0 Express your answer in terms of any or all of the quantities q R and C ANSWER 1 C ANSWER Correct Note that since current is charge per time the preceeding formula shows that the units of RC must be time The combination of variables 739 2 RC is called the time constant It will occur frequently in problems involving a resistor and a capacitor Problem 2181 Consider an RC circuit with 5 120 V R 165 Q and C 557 uF 12 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kirchhoff s Rules will b Part A Find the time constant for the circuit ANSWER 739 919 ms Correct Part B Find the maximum charge on the capacitor ANSWER Imam 668 MC Correct Part C Find the initial current in the circuit ANSWER 0 727 mA Correct https sessionmasteringphysics commyct as signmentPrintVieW displ Kirchhoff39s Current Rule Ranking Task The placement of resistors in a circuit is one factor that can determine the current passing through the resistor You will be given three circuits and for each circuit you will be asked to compare the current through the various resistors In each of the circuits all resistors are identical Part A Rank below the three identical resistors A B and C in on the basis of the current that flows through them Rank from largest to smallest To rank items as equivalent overlap them Hint 1 Kirchhoff39s current rule for circuit junctions Kirchhoff s current rule states that the current flowing into a junction a point at which the number of paths available for current flow changes must equal the current flowing out of the junction The portion of the current that flows through each available path depends on the resistance of each path Paths with less resistance will receive a larger share of the current 13 of16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kirchhoff s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 ANSWER Correct Part B Rank below the three identical resistors A B and C in on the basis of the current that flows through them Rank from largest to smallest To rank items as equivalent overlap them lll l Hint 1 Kirchhoff39s current rule for circuit junctions Kirchhoff s current rule states that the current flowing into a junction a point at which the number of paths available for current flow changes must equal the current flowing out of the junction The portion of the current that flows through each available path depends on the resistance of each path Paths with less resistance will receive a larger share of the current ANSWER 14 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kirchhoff s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 Correct Part C Rank below the four identical resistors A B C and D in on the basis of the current that flows through them Rank from largest to smallest To rank items as equivalent overlap them a I W if E D Hint 1 Kirchhoff39s current rule for circuit junctions Kirchhoff s current rule states that the current flowing into a junction a point at which the number of paths available for current flow changes must equal the current flowing out of the junction The portion of the current that flows through each available path depends on the resistance of each path Paths with less resistance will receive a larger share of the current ANSWER 15 of 16 3222016 747 PM Weekly Assignment 04 included in Exam 1 but Kircth s Rules will b httpssessionmasteringphysicscommyctassignmentPrintVieWdisp1 Correct Score Summary Your score on this assignment is 833 You received 10 out of a possible total of 12 points 16 of 16 3222016 747 PM

### BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.

### You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

## Why people love StudySoup

#### "Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

#### "Selling my MCAT study guides and notes has been a great source of side revenue while I'm in school. Some months I'm making over $500! Plus, it makes me happy knowing that I'm helping future med students with their MCAT."

#### "There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

#### "It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

### Refund Policy

#### STUDYSOUP CANCELLATION POLICY

All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email support@studysoup.com

#### STUDYSOUP REFUND POLICY

StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here: support@studysoup.com

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to support@studysoup.com

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.