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Physics: Principles with Applications | 7th Edition | ISBN: 9780321625922 | Authors: Douglas C. Giancoli
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Chapter 20 Problems

Chapter: 20 Problem: 21Q

Physics: Principles with Applications 7
Problem 21Q What would be the effect on B inside a long solenoid if (a) the diameter of all the loops was doubled, (b) the spacing between loops was doubled, or (c) the solenoids length was doubled along with a doubling in the total number of loops?

Chapter: 20 Problem: 22P

Physics: Principles with Applications 7
Problem 22P (III) A Hall probe, consisting of a thin rectangular slab of current-carrying material, is calibrated by placing it in a known magnetic field of magnitude 0.10 T. When the field is oriented normal to the slabs rectangular face, a Hall emf of 12 mV is measured across the slabs width. The

Chapter: 20 Problem: 22Q

Physics: Principles with Applications 7
A type of magnetic switch similar to a solenoid is a relay (Fig. 2050). A relay is an electromagnet (the iron rod inside the coil does not move) which, when activated, attracts a strip of iron on a pivot. Design a relay to close an electrical switch. A relay is used when you need to switch on a circu

Chapter: 20 Problem: 23P

Physics: Principles with Applications 7
Problem 23P (III) The Hall effect can be used to measure blood flow rate because the blood contains ions that constitute an electric current. (a) Does the sign of the ions influence the emf? Explain. (b) Determine the flow velocity in an artery 3.3mm in diameter if the measured emf across the width

Chapter: 20 Problem: 23Q

Physics: Principles with Applications 7
Two ions have the same mass, but one is singly ionized and the other is doubly ionized. How will their positions on the film of a mass spectrometer (Fig. 2041) differ? Explain.

Chapter: 20 Problem: 24P

Physics: Principles with Applications 7
(III) A long copper strip wide and thick is placed in a 1.2-T magnetic field as in Fig. 20-21a. When a steady current of 15 A passes through it, the Hall emf is measured to be \(1.02 \mu V\). Determine the drift velocity of the electrons and the density of free (conducting) electrons (number per

Chapter: 20 Problem: 24Q

Physics: Principles with Applications 7
Problem 24Q Why will either pole of a magnet attract an unmagnetized piece of iron?

Chapter: 20 Problem: 25P

Physics: Principles with Applications 7
Problem 25P (I) Jumper cables used to start a stalled vehicle often carry a 65-A current. How strong is the magnetic field 4.5 cm from one cable? Compare to the Earths magnetic field (5.0 X 10-5 T).

Chapter: 20 Problem: 25Q

Physics: Principles with Applications 7
Problem 25Q An unmagnetized nail will not attract an unmagnetized paper clip. However, if one end of the nail is in contact with a magnet, the other end will attract a paper clip. Explain.

Chapter: 20 Problem: 26P

Physics: Principles with Applications 7
(I) If an electric wire is allowed to produce a magnetic field no larger than that of the Earth \(0.50 \times 10^{-4} \ \mathrm t\) at a distance of 12 cm from the wire, what is the maximum current the wire can carry?

Chapter: 20 Problem: 27P

Physics: Principles with Applications 7
Problem 27P (I) Determine the magnitude and direction of the force between two parallel wires 25 m long and 4.0 cm apart, each carrying 25 A in the same direction.

Chapter: 20 Problem: 28P

Physics: Principles with Applications 7
Problem 28P (I) A vertical straight wire carrying an upward 28-A current exerts an attractive force per unit length of 7.8 X 10-4 N/m on a second parallel wire 9.0 cm away. What current (magnitude and direction) flows in the second wire?

Chapter: 20 Problem: 29P

Physics: Principles with Applications 7
(II) In Fig. 20-54, a long straight wire carries current out of the page toward you. Indicate, with appropriate arrows, the direction and (relative) magnitude of \(\vec{B}\) at each of the points , and in the plane of the page. Equation transcription: Text transcription: vec{B}

Chapter: 20 Problem: 30P

Physics: Principles with Applications 7
Problem 30P (II) An experiment on the Earths magnetic field is being carried out 1.00 m from an electric cable. What is the maximum allowable current in the cable if the experiment is to be accurate to 3.0%?

Chapter: 20 Problem: 31P

Physics: Principles with Applications 7
(II) A rectangular loop of wire is placed next to a straight wire, as shown in Fig. 2055. There is a current of 3.5 A in both wires. Determine the magnitude and direction of the net force on the loop. \(3.5 A\) \(3.5 A\) \(3.0 \mathrm{~cm}\) \(10.0 \mathrm{~cm}\) Equation transcription: T

Chapter: 20 Problem: 32P

Physics: Principles with Applications 7
Problem 32P (II) A horizontal compass is placed 18 cm due south from a straight vertical wire carrying a 48-A current downward. In what direction does the compass needle point at this location? Assume the horizontal component of the Earths field at this point is 0.45 X 10-4 T and the magnetic decli

Chapter: 20 Problem: 33P

Physics: Principles with Applications 7
Problem 33P (II) A long horizontal wire carries 24.0 A of current due north. What is the net magnetic field 20.0 cm due west of the wire if the Earths field there points downward, 44 below the horizontal, and has magnitude 5.0 X 10-5 T?

Chapter: 20 Problem: 34P

Physics: Principles with Applications 7
Problem 34P (II) A straight stream of protons passes a given point in space at a rate of 2.5 X 109 protons/s. What magnetic field do they produce 1.5 m from the beam?

Chapter: 20 Problem: 35P

Physics: Principles with Applications 7
Problem 35P (II) Determine the magnetic field midway between two long straight wires 2.0 cm apart in terms of the current I in one when the other carries 25 A. Assume these currents are (a) in the same direction, and (b) in opposite directions.

Chapter: 20 Problem: 36P

Physics: Principles with Applications 7
Problem 36P (II) Two straight parallel wires are separated by 7.0 cm. There is a 2.0-A current flowing in the first wire. If the magnetic field strength is found to be zero between the two wires at a distance of 2.2 cm from the first wire, what is the magnitude and direction of the current in the s

Chapter: 20 Problem: 37P

Physics: Principles with Applications 7
(II) Two long straight wires each carry a current I out of the page toward the viewer, Fig. 2056. Indicate, with appropriate arrows, the direction of \(\vec {\mathrm B}\) at each of the points 1 to 6 in the plane of the page. State if the field is zero at any of the points.

Chapter: 20 Problem: 38P

Physics: Principles with Applications 7
(II) A power line carries a current of 95 A west along the tops of 8.5-m-high poles. (a) What is the magnitude and direction of the magnetic field produced by this wire at the ground directly below? How does this compare with the Earths magnetic field of about \(\frac{1}{2} G\)? (b) Where would the w

Chapter: 20 Problem: 39P

Physics: Principles with Applications 7
Problem 39P (II) A compass needle points 17 E of N outdoors. However, when it is placed 12.0 cm to the east of a vertical wire inside a building, it points 32 E of N. What is the magnitude and direction of the current in the wire? The Earths field there is 0.50 X 104 T and is horizontal.

Chapter: 20 Problem: 40P

Physics: Principles with Applications 7
(II) A long pair of insulated wires serves to conduct 24.5 A of dc current to and from an instrument. If the wires are of negligible diameter but are 2.8 mm apart, what is the magnetic field 10.0 cm from their midpoint, in their plane (Fig.2057)? Compare to the magnetic field of the Earth. \(10.0 \

Chapter: 20 Problem: 41P

Physics: Principles with Applications 7
Problem 41P (II) A third wire is placed in the plane of the two wires shown in Fig. 2057 parallel and just to the right. If it carries 25.0 A upward, what force per meter of length does it exert on each of the other two wires? Assume it is 2.8mm from the nearest wire, center to center.

Chapter: 20 Problem: 42P

Physics: Principles with Applications 7
(III) Two long thin parallel wires 13.0 cm apart carry 28-A currents in the same direction. Determine the magnetic field vector at a point 10.0 cm from one wire and 6.0 cm from the other (Fig. 2058). \(6.0 \mathrm{~cm}\) \(13.0 \mathrm{~cm}\) \(10.0 \mathrm{~cm}\) Equation transcription: Tex

Chapter: 20 Problem: 43P

Physics: Principles with Applications 7
(III) Two long wires are oriented so that they are perpendicular to each other. At their closest, they are 20.0 cm apart (Fig. 2059). What is the magnitude of the magnetic field at a point midway between them if the top one carries a current of 20.0 A and the bottom one carries 12.0 A? \(I_{T}=20.0

Chapter: 20 Problem: 44P

Physics: Principles with Applications 7
Problem 44P (I) A thin 12-cm-long solenoid has a total of 460 turns of wire and carries a current of 2.0 A. Calculate the field inside the solenoid near the center.

Chapter: 20 Problem: 45P

Physics: Principles with Applications 7
Problem 45P (I) A 30.0-cm-long solenoid 1.25 cm in diameter is to produce a field of 4.65 mT at its center. How much current should the solenoid carry if it has 935 turns of the wire?

Chapter: 20 Problem: 46P

Physics: Principles with Applications 7
Problem 46P (I) A 42-cm-long solenoid, 1.8 cm in diameter, is to produce a 0.030-T magnetic field at its center. If the maximum current is 4.5 A, how many turns must the solenoid have?

Chapter: 20 Problem: 47P

Physics: Principles with Applications 7
Problem 47P (II) A 550-turn horizontal solenoid is 15 cm long. The current in its coils is 38 A. A straight wire cuts through the center of the solenoid, along a 3.0-cm diameter. This wire carries a 22-A current downward (and is connected by other wires that dont concern us). What is the force on t

Chapter: 20 Problem: 48P

Physics: Principles with Applications 7
Problem 48P (III) You have 1.0 kg of copper and want to make a practical solenoid that produces the greatest possible magnetic field for a given voltage. Should you make your copper wire long and thin, short and fat, or something else? Consider other variables, such as solenoid diameter, length, an

Chapter: 20 Problem: 49P

Physics: Principles with Applications 7
(III) A toroid is a solenoid in the shape of a donut (Fig. 2060). Use Ampres law along the circular paths, shown dashed in Fig. 2060a, to determine that the magnetic field () inside the toroid is B = \(\mu_{a} N I \backslash 2 \pi R\), where N is the total number of turns, and (b) outside the toroid

Chapter: 20 Problem: 50P

Physics: Principles with Applications 7
(III) () Use Ampres law to show that the magnetic field between the conductors of a coaxial cable (Fig. 2061) is \(B=\mu_{a} \backslash 2 \pi r\) if r (distance from center) is greater than the radius of the inner wire and less than the radius of the outer cylindrical braid (= ground). (b) Show that

Chapter: 20 Problem: 51P

Physics: Principles with Applications 7
Problem 51P (I) A single square loop of wire 22.0 cm on a side is placed with its face parallel to the magnetic field as in Fig. 2034b. When 5.70 A flows in the coil, the torque on it is 0.325 m.N. What is the magnetic field strength?

Chapter: 20 Problem: 52P

Physics: Principles with Applications 7
Problem 52P (I) If the current to a motor drops by 12%, by what factor does the output torque change?

Chapter: 20 Problem: 53P

Physics: Principles with Applications 7
Problem 53P (I) A galvanometer needle deflects full scale for a 53.0 A current. What current will give full-scale deflection if the magnetic field weakens to 0.760 of its original value?

Chapter: 20 Problem: 54P

Physics: Principles with Applications 7
Problem 54P (II) A circular coil 12.0 cm in diameter and containing nine loops lies flat on the ground. The Earths magnetic field at this location has magnitude 5.50 X 10-5 T and points into the Earth at an angle of 56.0 below a line pointing due north. If a 7.20-A clockwise current passes through

Chapter: 20 Problem: 55P

Physics: Principles with Applications 7
Problem 55P (I) Protons move in a circle of radius 6.10 cm in a 0.566-T magnetic field. What value of electric field could make their paths straight? In what direction must the electric field point?

Chapter: 20 Problem: 57P

Physics: Principles with Applications 7
(II) Suppose the electric field between the electric plates in the mass spectrometer of Fig. 2041 is \(2.88 \times 10^{4} \mathrm{~V} / \mathrm{m}\) and the magnetic fields are \(B=B^{\prime}=0.68 T\). The source contains carbon isotopes of mass numbers 12, 13, and 14 from a long-dead piece of a tree

Chapter: 20 Problem: 56P

Physics: Principles with Applications 7
Problem 56P (I) Protons move in a circle of radius 6.10 cm in a 0.566-T magnetic field. What value of electric field could make their paths straight? In what direction must the electric field point?

Chapter: 20 Problem: 58P

Physics: Principles with Applications 7
Problem 58P (II) One form of mass spectrometer accelerates ions by a voltage V before they enter a magnetic field B. The ions are assumed to start from rest. Show that the mass of an ion m =qB2R2/2V, is where R is the radius of the ions path in the magnetic field and q is their charge.

Chapter: 20 Problem: 59P

Physics: Principles with Applications 7
Problem 59P (II) An unknown particle moves in a straight line through crossed electric and magnetic fields with E = 1.5 KV/m and B =0.034T. If the electric field is turned off, the particle moves in a circular path of radius r =2.7 cm. What might the particle be?

Chapter: 20 Problem: 60P

Physics: Principles with Applications 7
(III) A mass spectrometer is monitoring air pollutants. It is difficult, however, to separate molecules of nearly equal mass such as CO (28.0106 u) and \(N_{2}\) (28.0134 u). How large a radius of curvature must a spectrometer have (Fig. 2041) if these two molecules are to be separated on the film b

Chapter: 20 Problem: 61P

Physics: Principles with Applications 7
Problem 61P (I) A long thin iron-core solenoid has 380 loops of wire per meter, and a 350-mA current flows through the wire. If the permeability of the iron is 3000 0, what is the total field B inside the solenoid?

Chapter: 20 Problem: 62P

Physics: Principles with Applications 7
Problem 62P (II) An iron-core solenoid is 38 cm long and 1.8 cm in diameter, and has 780 turns of wire. The magnetic field inside the solenoid is 2.2 T when 48 A flows in the wire. What is the permeability at this high field strength?

Chapter: 20 Problem: 63P

Physics: Principles with Applications 7
Problem 63P (II) The following are some values of B and B0 for a piece of iron as it is being magnetized (note different units): B0 (10-4 T) 0.0 0.13 0.25 0.50 0.63 0.78 1.0 1.3 B(T) 0.0 0.0042 0.010 0.028 0.043 0.095 0.45 0.67 B0 (10-4 T) 1.9 2.5 6.3 13.0 130 1300 10,000 B(T) 1.01 1.18 1.44 1.58

Chapter: 20 Problem: 64GP

Physics: Principles with Applications 7
Problem 64GP Two long straight parallel wires are 15 cm apart. Wire A carries 2.0-A current. Wire Bs current is 4.0 A in the same direction. (a) Determine the magnetic field magnitude due to wire A at the position of wire B. (b) Determine the magnetic field due to wire B at the position of wire A.

Chapter: 20 Problem: 65GP

Physics: Principles with Applications 7
Problem 65GP Protons with momentum 4.8*10-21 kg.m/s are magnetically steered clockwise in a circular path 2.2 m in diameter. Determine the magnitude and direction of the field in the magnets surrounding the beam pipe.

Chapter: 20 Problem: 66GP

Physics: Principles with Applications 7
A small but rigid wire carrying a 5.0-A current (Fig. 2062) is placed inside a solenoid. The solenoid is 15.0 cm long and has 700 loops of wire, and the current in each loop is 7.0 A. What is the net force on the -shaped wire? FIGURE 2062 Problem 66.

Chapter: 20 Problem: 67GP

Physics: Principles with Applications 7
The power cable for an electric trolley (Fig. 2063) carries a horizontal current of 330 A toward the east. The Earths magnetic field has a strength \(5.0 \times 10^{-5} T\) and makes an angle of dip of 22 at this location. Calculate the magnitude and direction of the magnetic force on an 18-m length

Chapter: 20 Problem: 68GP

Physics: Principles with Applications 7
Problem 68GP A particle of charge q moves in a circular path of radius r perpendicular to a uniform magnetic field B. Determine its linear momentum in terms of the quantities given.

Chapter: 20 Problem: 69GP

Physics: Principles with Applications 7
Problem 69GP An airplane has acquired a net charge of 1280 C. If the Earths magnetic field of 5.0 x 10-5 T is perpendicular to the airplanes velocity of magnitude 120 m/s, determine the force on the airplane.

Chapter: 20 Problem: 70GP

Physics: Principles with Applications 7
Problem 70GP A 32-cm-long solenoid, 1.8 cm in diameter, is to produce a 0.050-T magnetic field at its center. If the maximum current is 6.4 A, how many turns must the solenoid have?

Chapter: 20 Problem: 71GP

Physics: Principles with Applications 7
Problem 71GP Near the equator, the Earths magnetic field points almost horizontally to the north and has magnitude B=0.50*10-4 T. What should be the magnitude and direction for the velocity of an electron if its weight is to be exactly balanced by the magnetic force?

Chapter: 20 Problem: 72GP

Physics: Principles with Applications 7
Problem 72GP A doubly charged helium atom, whose mass is 6.6*10-27 kg, is accelerated by a voltage of 3200 V. (a) What will be its radius of curvature in a uniform 0.240-T field? (b) What is its period of revolution?

Chapter: 20 Problem: 73GP

Physics: Principles with Applications 7
Four very long straight parallel wires, located at the corners of a square of side , carry equal currents \(I_{0}\) perpendicular to the page as shown in Fig. 2064. Determine the magnitude and direction \(\vec{B}\) of at the center C of the square. FIGURE 2064 Problem 73. Equation transcripti

Chapter: 20 Problem: 74GP

Physics: Principles with Applications 7
Problem 74GP (a) What value of magnetic field would make a beam of electrons, traveling to the west at a speed of 4.8*106 m/s, go undeflected through a region where there is a uniform electric field of 12000 V/m pointing south? (b) What is the direction of the magnetic field if it is perpendicular

Chapter: 20 Problem: 75GP

Physics: Principles with Applications 7
Magnetic fields are very useful in particle accelerators for beam steering; that is, the magnetic fields can be used to change the direction of the beam of charged particles without altering their speed (Fig. 2065). Show how this could work with a beam of protons. What happens to protons that are not

Chapter: 20 Problem: 76GP

Physics: Principles with Applications 7
The magnetic field at the center of a circular coil of wire carrying a current (as in Fig. is \(B=\frac{\mu_{0} N L}{2 r}\) where is the number of loops in the coil and is its radius. Imagine a simple model in which the Earth's magnetic field of about \(1 G\left(=1 \times 10^{-4} T\right)\) near

Chapter: 20 Problem: 77GP

Physics: Principles with Applications 7
A proton follows a spiral path through a gas in a uniform magnetic field of \(0.010 \mathrm{~T}\), perpendicular to the plane of the spiral, as shown in Fig. 2066. In two successive loops, at points P and Q, the radii are 10.0 mm and 8.5 mm, respectively. Calculate the change in the kinetic energy of

Chapter: 20 Problem: 78GP

Physics: Principles with Applications 7
Two long straight aluminum wires, each of diameter 0.42 mm, carry the same current but in opposite directions. They are suspended by 0.50-m-long strings as shown in Fig. 2067. If the suspension strings make an angle of \(3.0^{0}\) with the vertical and are hanging freely, what is the current in the w

Chapter: 20 Problem: 79GP

Physics: Principles with Applications 7
Problem 79GP An electron enters a uniform magnetic field B = 0.23 T at a 45 angle to Determine the radius r and pitch p (distance between loops) of the electrons helical path assuming its speed is 3.0 x 106 m/s. See Fig. 2068.

Chapter: 20 Problem: 80GP

Physics: Principles with Applications 7
Problem 80GP A motor run by a 9.0-V battery has a 20-turn square coil with sides of length 5.0 cm and total resistance 28 ?. When spinning, the magnetic field felt by the wire in the coil is 0.020 T. What is the maximum torque on the motor?

Chapter: 20 Problem: 81GP

Physics: Principles with Applications 7
Problem 81GP Electrons are accelerated horizontally by 2.2 kV. They then pass through a uniform magnetic field B for a distance of 3.8 cm, which deflects them upward so they reach the top of a screen 22 cm away, 11 cm above the center. Estimate the value of B.

Chapter: 20 Problem: 82GP

Physics: Principles with Applications 7
Problem 82GP A 175-g model airplane charged to 18.0 mC and traveling at 3.4 m/s passes within 8.6 cm of a wire, nearly parallel to its path, carrying a 25-A current.What acceleration (in gs) does this interaction give the airplane?

Chapter: 20 Problem: 83GP

Physics: Principles with Applications 7
A uniform conducting rod of length and mass m sits atop a fulcrum, which is placed a distance \(I / 4\) from the rods left-hand end and is immersed in a uniform magnetic field of magnitude directed into the page (Fig. 2069). An object whose mass is 6.0 times greater than the rods mass is hung from t

Chapter: 20 Problem: 84GP

Physics: Principles with Applications 7
Problem 84GP Suppose the Earths magnetic field at the equator has Magnitude 0.50 x 10-4 T and a northerly direction at all points. Estimate the speed a singly ionized uranium ion (m = 238, q = +e) would need to circle the Earth 6.0 km above the equator. Can you ignore gravity? [Ignore relativity.]

Chapter: 20 Problem: 85GP

Physics: Principles with Applications 7
A particle with charge and momentum , initially moving along the axis, enters a region where a uniform magnetic field \(B_{0}\) extends over a width as shown in Fig. 2070. The particle is deflected a distance in the direction as it traverses the field. Determine (a) whether is positive or negative,

Chapter: 20 Problem: 86GP

Physics: Principles with Applications 7
Problem 86GP A bolt of lightning strikes a metal flag pole, one end of which is anchored in the ground. Estimate the force the Earths magnetic field can exert on the flag pole while the lightning-induced current flows. See Example 1810.

Chapter: 20 Problem: 87GP

Physics: Principles with Applications 7
A sort of projectile launcher is shown in Fig. 2071. A large current moves in a closed loop composed of fixed rails, a power supply, and a very light, almost frictionless bar (pale green) touching the rails. A magnetic field is perpendicular to the plane of the circuit. If the bar has a length \(I=2

Chapter: 20 Problem: 88GP

Physics: Principles with Applications 7
The cyclotron (Fig. 20-72 ) is a device used to accelerate elementary particles such as protons to high speeds. Particles starting at point A with some initial velocity travel in semicircular orbits in the magnetic field B. The particles are accelerated to higher speeds each time they pass through th

Chapter: 20 Problem: 89GP

Physics: Principles with Applications 7
Three long parallel wires are 3.8 cm from one another. (Looking along them, they are at three corners of an equilateral triangle.) The current in each wire is 8.00 A, but its direction in wire M is opposite to that in wires N and P (Fig. 2073). (a) Determine the magnetic force per unit length on each

Chapter: 20 Problem: 90GP

Physics: Principles with Applications 7
In Fig. 2073 the top wire is 1.00-mm-diameter copper wire and is suspended in air due to the two magnetic forces from the bottom two wires. The current flow through the two bottom wires is 75 A in each. Calculate the required current flow in the suspended wire (M).

Chapter: 20 Problem: 91GP

Physics: Principles with Applications 7
Problem 91GP You want to get an idea of the magnitude of magnetic fields produced by overhead power lines. You estimate that a transmission wire is about 13 m above the ground. The local power company tells you that the lines operate at 240 kV and provide a maximum power of 46 MW. Estimate the magn

Chapter: 20 Problem: 92GP

Physics: Principles with Applications 7
Two long parallel wires 8.20 cm apart carry 19.2-A currents in the same direction. Determine the magnetic field vector at a point P, 12.0 cm from one wire and 13.0 cm from the other (Fig. 2074). [Hint: Use the law of cosines; see Appendix A or inside rear cover.] FIGURE 2074 Problem 92.

Chapter: 20 Problem: 1COQ

Physics: Principles with Applications 7
Problem 1COQ Which of the following can experience a force when placed in the magnetic field of a magnet? (a) An electric charge at rest. (c) An electric current in a wire. (b) An electric charge moving. (d) Another magnet.

Chapter: 20 Problem: 1MCQ

Physics: Principles with Applications 7
Problem 1MCQ Indicate which of the following will produce a magnetic field: (a) A magnet. (b) The Earth. (c) An electric charge at rest. (d) A moving electric charge. (e) An electric current. (f ) The voltage of a battery not connected to anything. (g) An ordinary piece of iron. (h) A piece of any

Chapter: 20 Problem: 1P

Physics: Principles with Applications 7
Problem 1P (I) (a) What is the force per meter of length on a straight wire carrying a 6.40-A current when perpendicular to a 0.90-T uniform magnetic field? (b) What if the angle between the wire and field is 35.0?

Chapter: 20 Problem: 1Q

Physics: Principles with Applications 7
Problem 1Q A compass needle is not always balanced parallel to the Earths surface, but one end may dip downward. Explain.

Chapter: 20 Problem: 1SL

Physics: Principles with Applications 7
Problem 1SL How many magnetic force equations are there in Chapter 20? List each one and explain when it applies. For each magnetic force equation, show how the units work out to give force in newtons.

Chapter: 20 Problem: 2MCQ

Physics: Principles with Applications 7
A current in a wire points into the page as shown at the right. In which direction is the magnetic field at point A (choose below)?

Chapter: 20 Problem: 2P

Physics: Principles with Applications 7
How much current is flowing in a wire 4.80 m long if the maximum force on it is 0.625 N when placed in a uniform 0.0800-T field?

Chapter: 20 Problem: 2Q

Physics: Principles with Applications 7
Problem 2Q Explain why the Earths north pole is really a magnetic south pole. Indicate how north and south magnetic poles were defined and how we can tell experimentally that the north pole is really a south magnetic pole.

Chapter: 20 Problem: 2SL

Physics: Principles with Applications 7
Problem 2SL An electron is moving north at a constant speed of 3.0 X 104 m/s. (a) In what direction should an electric field point if the electron is to be accelerated to the east? (b) In what direction should a magnetic field point if the electron is to be accelerated to the west? (c) If the elect

Chapter: 20 Problem: 3MCQ

Physics: Principles with Applications 7
Problem 3MCQ In which direction (see above) is the magnetic field at point B?

Chapter: 20 Problem: 3P

Physics: Principles with Applications 7
Problem 3P (I) A 240-m length of wire stretches between two towers and carries a 120-A current. Determine the magnitude of the force on the wire due to the Earths magnetic field of 5.0 X 10-5 which makes an angle of 68 with the wire.

Chapter: 20 Problem: 3Q

Physics: Principles with Applications 7
Problem 3Q In what direction are the magnetic field lines surrounding a straight wire carrying a current that is moving directly away from you? Explain.

Chapter: 20 Problem: 3SL

Physics: Principles with Applications 7
() A particle of charge q moves in a circular path of radius r in a uniform magnetic field \(\vec{B}\).If the magnitude of the magnetic field is double, and the kinetic energy of the particle is the same, how does the angular momentum of the particle differ? (b) Show that the magnetic dipole moment M

Chapter: 20 Problem: 4MCQ

Physics: Principles with Applications 7
Problem 4MCQ When a charged particle moves parallel to the direction of a magnetic field, the particle travels in a (a) straight line. (c) helical path. (b) circular path. (d) hysteresis loop.

Chapter: 20 Problem: 4P

Physics: Principles with Applications 7
Problem 4P (I) A 2.6-m length of horizontal wire carries a 4.5-A current toward the south. The dip angle of the Earths magnetic field makes an angle of 41 to the wire. Estimate the magnitude of the magnetic force on the wire due to the Earths magnetic field of 5.5 X 10-5 T.

Chapter: 20 Problem: 4Q

Physics: Principles with Applications 7
Problem 4Q A horseshoe magnet is held vertically with the north pole on the left and south pole on the right. A wire passing between the poles, equidistant from them, carries a current directly away from you. In what direction is the force on the wire? Explain.

Chapter: 20 Problem: 4SL

Physics: Principles with Applications 7
(a) Two long parallel wires, each 2.0 mm in diameter and 9.00 cm apart, carry equal 1.0-A currents in the same direction, Fig. 2075. Determine \(\vec{B}\) along the x axis between the wires as a function of x. (b) Graph B vs. x from x = 1.0 mm to x =89.0 mm. \(d=9.00 \mathrm{~cm}\) Equation

Chapter: 20 Problem: 5MCQ

Physics: Principles with Applications 7
Problem 5MCQ As a proton moves through space, it creates (a) an electric field only. (b) a magnetic field only. (c) both an electric field and magnetic field. (d) nothing; the electric field and magnetic fields cancel each other out.

Chapter: 20 Problem: 5P

Physics: Principles with Applications 7
Problem 5P (I) The magnetic force per meter on a wire is measured to be only 45% of its maximum possible value. What is the angle between the wire and the magnetic field?

Chapter: 20 Problem: 5Q

Physics: Principles with Applications 7
Problem 5Q Will a magnet attract any metallic object, such as those made of aluminum or copper? (Try it and see.) Why is this so?

Chapter: 20 Problem: 5SL

Physics: Principles with Applications 7
The force on a moving particle in a magnetic field is the idea behind electromagnetic pumping. It can be used to pump metallic fluids (such as sodium) and to pump blood in artificial heart machines. A basic design is shown in Fig. 2076. For blood, an electric field is applied perpendicular to a blood

Chapter: 20 Problem: 6MCQ

Physics: Principles with Applications 7
Problem 6MCQ Which statements about the force on a charged particle placed in a magnetic field are true? (a) A magnetic force is exerted only if the particle is moving. (b) The force is a maximum if the particle is moving in the direction of the field. (c) The force causes the particle to gain kine

Chapter: 20 Problem: 6P

Physics: Principles with Applications 7
Problem 6P (II) The force on a wire carrying 6.45 A is a maximum of 1.28 N when placed between the pole faces of a magnet. If the pole faces are 55.5 cm in diameter, what is the approximate strength of the magnetic field?

Chapter: 20 Problem: 6Q

Physics: Principles with Applications 7
Problem 6Q Two iron bars attract each other no matter which ends are placed close together. Are both magnets? Explain.

Chapter: 20 Problem: 7MCQ

Physics: Principles with Applications 7
Problem 7MCQ Which of the following statements is false? The magnetic field of a current-carrying wire (a) is directed circularly around the wire. (b) decreases inversely with the distance from the wire. (c) exists only if the current in the wire is changing. (d) depends on the magnitude of the cur

Chapter: 20 Problem: 7P

Physics: Principles with Applications 7
Problem 7P (II) The force on a wire is a maximum of 8.50 X 10-2 N when placed between the pole faces of a magnet. The current flows horizontally to the right and the magnetic field is vertical. The wire is observed to jump toward the observer when the current is turned on. (a) What type of magnetic

Chapter: 20 Problem: 7Q

Physics: Principles with Applications 7
Problem 7Q The magnetic field due to current in wires in your home can affect a compass. Discuss the effect in terms of currents, including if they are ac or dc.

Chapter: 20 Problem: 8MCQ

Physics: Principles with Applications 7
Problem 8MCQ A wire carries a current directly away from you. Which way do the magnetic field lines produced by this wire point? (a) They point parallel to the wire in the direction of the current. (b) They point parallel to the wire opposite the direction of the current. (c) They point toward the

Chapter: 20 Problem: 8P

Physics: Principles with Applications 7
(II) Suppose a straight 1.00-mm-diameter copper wire could just float horizontally in air because of the force due to the Earths magnetic field \(\vec{B}\), which is horizontal, perpendicular to the wire, and of magnitude \(5.0 \times 10^{-5} T\). What current would the wire carry? Does the answer se

Chapter: 20 Problem: 8Q

Physics: Principles with Applications 7
Problem 8Q If a negatively charged particle enters a region of uniform magnetic field which is perpendicular to the particles velocity, will the kinetic energy of the particle increase, decrease, or stay the same? Explain your answer. (Neglect gravity and assume there is no electric field.)

Chapter: 20 Problem: 9MCQ

Physics: Principles with Applications 7
A proton enters a uniform magnetic field that is perpendicular to the protons velocity (Fig. 2051). What happens to the kinetic energy of the proton? () It increases. (b) It decreases. (c) It stays the same. (d) It depends on the velocity direction. (e) It depends on the B field direction.

Chapter: 20 Problem: 9P

Physics: Principles with Applications 7
Problem 9P (I) Determine the magnitude and direction of the force on an electron traveling 7.75 X 105 m/s horizontally to the east in a vertically upward magnetic field of strength 0.45 T.

Chapter: 20 Problem: 9Q

Physics: Principles with Applications 7
In Fig. 2047, charged particles move in the vicinity of a current-carrying wire. For each charged particle, the arrow indicates the initial direction of motion of the particle, and the + or - indicates the sign of the charge. For each of the particles, indicate the direction of the magnetic force due

Chapter: 20 Problem: 10MCQ

Physics: Principles with Applications 7
Problem 10MCQ For a charged particle, a constant magnetic field can be used to change (a) only the direction of the particles velocity. (b) only the magnitude of the particles velocity. (c) both the magnitude and direction of the particles velocity. (d) None of the above.

Chapter: 20 Problem: 10P

Physics: Principles with Applications 7
Problem 10P (I) An electron is projected vertically upward with a speed Of 1.70 X 106 into a uniform magnetic field of 0.640 T that is directed horizontally away from the observer. Describe the electrons path in this field.

Chapter: 20 Problem: 10Q

Physics: Principles with Applications 7
Three particles, a, b, and c, enter a magnetic field and follow paths as shown in Fig. 2048. What can you say about the charge on each particle? Explain.

Chapter: 20 Problem: 11MCQ

Physics: Principles with Applications 7
Which of the following statements about the force on a charged particle due to a magnetic field are not valid? (a) It depends on the particles charge. (b) It depends on the particles velocity. (c) It depends on the strength of the external magnetic field. (d) It acts at right angles t

Chapter: 20 Problem: 11P

Physics: Principles with Applications 7
(I) Alpha particles (charge q = +2e, mass \(m = 6.6 \times 10^{-27}\ kg\) move at \(1.6 \times 10^6 m/s\). What magnetic field strength would be required to bend them into a circular path of radius r = 0.14 m?

Chapter: 20 Problem: 11Q

Physics: Principles with Applications 7
Problem 11Q Can an iron rod attract a magnet? Can a magnet attract an iron rod?What must you consider to answer these questions?

Chapter: 20 Problem: 12MCQ

Physics: Principles with Applications 7
Problem 12MCQ Two parallel wires are vertical. The one on the left carries a 10-A current upward. The other carries 5-A current downward. Compare the magnitude of the force that each wire exerts on the other. (a) The wire on the left carries twice as much current, so it exerts twice the force on th

Chapter: 20 Problem: 12P

Physics: Principles with Applications 7
(I) Find the direction of the force on a negative charge for each diagram shown in Fig. 2052, where (green) is the velocity of the charge and \(\vec{B}\) (blue) is the direction of the magnetic field. ( ? means the vector points inward. means it points outward, toward you.) \(\vec{B}\) \(\vec{v}\

Chapter: 20 Problem: 12Q

Physics: Principles with Applications 7
A positively charged particle in a nonuniform magnetic field follows the trajectory shown in Fig. 2049. Indicate the direction of the magnetic field at points near the path, assuming the path is always in the plane of the page, and indicate the relative magnitudes of the field in each region. Explain

Chapter: 20 Problem: 13P

Physics: Principles with Applications 7
(I) Determine the direction of \(\vec{B}\) for each case in Fig. 2053, where \(\vec{F}\) represents the maximum magnetic force on a positively charged particle moving with velocity \(\vec{v}\). \(\vec{F}\) \(\vec{B}\) \(\vec{v}\) Equation transcription: Text transcription: vec{B} vec{F} ve

Chapter: 20 Problem: 13Q

Physics: Principles with Applications 7
Problem 13Q Explain why a strong magnet held near a CRT television screen (Section 1711) causes the picture to become distorted. Also, explain why the picture sometimes goes completely black where the field is the strongest. [But dont risk damage to your TV by trying this.]

Chapter: 20 Problem: 14P

Physics: Principles with Applications 7
(II) What is the velocity of a beam of electrons that goes undeflected when moving perpendicular to an electric and to a magnetic field. \(\vec{E}\) and \(\vec{B}\) are also perpendicular to each other and have magnitudes \(7.7 x 10^{-3} T\), and respectively. What is the radius of the electron orbit

Chapter: 20 Problem: 14Q

Physics: Principles with Applications 7
Problem 14Q Suppose you have three iron rods, two of which are magnetized but the third is not. How would you determine which two are the magnets without using any additional objects?

Chapter: 20 Problem: 15P

Physics: Principles with Applications 7
Problem 15P (II) A helium ion (Q =+2e) whose mass is 6.6 C 10-27 kg is accelerated by a voltage of 3700 V. (a)What is its speed? (b) What will be its radius of curvature if it moves in a plane perpendicular to a uniform 0.340-T field? (c) What is its period of revolution?

Chapter: 20 Problem: 15Q

Physics: Principles with Applications 7
Problem 15Q Can you set a resting electron into motion with a magnetic field? With an electric field? Explain.

Chapter: 20 Problem: 16P

Physics: Principles with Applications 7
Problem 16P (II) For a particle of mass m and charge q moving in a circular path in a magnetic field B, (a) show that its kinetic energy is proportional to r2 the square of the radius of curvature of its path. (b) Show that its angular momentum is L =q Br2 around the center of the circle.

Chapter: 20 Problem: 16Q

Physics: Principles with Applications 7
Problem 16Q A charged particle is moving in a circle under the influence of a uniform magnetic field. If an electric field that points in the same direction as the magnetic field is turned on, describe the path the charged particle will take.

Chapter: 20 Problem: 17P

Physics: Principles with Applications 7
(II) A 1.5-MeV (kinetic energy) proton enters a 0.30-T field, in a plane perpendicular to the field. What is the radius of its path? See Section 174.

Chapter: 20 Problem: 17Q

Physics: Principles with Applications 7
Problem 17Q A charged particle moves in a straight line through a particular region of space. Could there be a nonzero magnetic field in this region? If so, give two possible situations.

Chapter: 20 Problem: 18P

Physics: Principles with Applications 7
Problem 18P (II) An electron experiences the greatest force as it travels 2.8 X 106 m/s in a magnetic field when it is moving north-ward. 6.2 X 10-13 N. The force is vertically upward and of magnitude What is the magnitude and direction of the magnetic field?

Chapter: 20 Problem: 18Q

Physics: Principles with Applications 7
Problem 18Q If a moving charged particle is deflected sideways in some region of space, can we conclude, for certain, that in that region? Explain.

Chapter: 20 Problem: 19P

Physics: Principles with Applications 7
Problem 19P (II) A proton and an electron have the same kinetic energy upon entering a region of constant magnetic field. What is the ratio of the radii of their circular paths?

Chapter: 20 Problem: 19Q

Physics: Principles with Applications 7
Problem 19Q Two insulated long wires carrying equal currents I cross at right angles to each other. Describe the magnetic force one exerts on the other.

Chapter: 20 Problem: 20EA

Physics: Principles with Applications 7
Does the Earths magnetic field have a greater magnitude near the poles or near the equator? [How can you tell using the field lines in Fig. 205?]

Chapter: 20 Problem: 20EB

Physics: Principles with Applications 7
Problem 20EB A straight wire carries a current directly toward you. In what direction are the magnetic field lines surrounding the wire?

Chapter: 20 Problem: 20ED

Physics: Principles with Applications 7
Problem 20ED A straight power line carries 30 A and is perpendicular to the Earths magnetic field of 0.50 X 104 T.What magnitude force is exerted on 100m of this power line?

Chapter: 20 Problem: 20EC

Physics: Principles with Applications 7
Problem 20EC A wire carrying current I is perpendicular to a magnetic field of strength B. Assuming a fixed length of wire, which of the following changes will result in decreasing the force on the wire by a factor of 2? (a) Decrease the angle from 90 to 45; (b) decrease the angle from 90 to 30; (c

Chapter: 20 Problem: 20EE

Physics: Principles with Applications 7
Return to the Chapter-Opening Question, page 560, and answer it again now. Try to explain why you may have answered differently the first time.

Chapter: 20 Problem: 20EG

Physics: Principles with Applications 7
What is the sign of the charge in Fig. 2019? How would you modify the drawing if the charge had the opposite sign?

Chapter: 20 Problem: 20EH

Physics: Principles with Applications 7
Suppose both \(I_{1}\) and \(I_{2}\) point into the page in Fig. 2024. What then is the field B midway between the wires? Equation transcription: Text transcription: I{1} I{2}

Chapter: 20 Problem: 20P

Physics: Principles with Applications 7
(III) A proton (mass \(m_{p}\) ), a deuteron \(\left(m=2 m_{p}, Q=e\right)\), and an alpha particle \(\left(m=4 m_{p}, Q=2 e\right)\) are accelerated by the same potential difference and then enter a uniform magnetic field , where they move in circular paths perpendicular to . Determine the radius o

Chapter: 20 Problem: 20Q

Physics: Principles with Applications 7
Problem 20Q A horizontal current-carrying wire, free to move in Earths gravitational field, is suspended directly above a parallel, current-carrying wire. (a) In what direction is the current in the lower wire? (b) Can the lower wire be held in stable equilibrium due to the magnetic force of the up

Chapter: 20 Problem: 21P

Physics: Principles with Applications 7
Problem 21P (III) A 3.40-g bullet moves with a speed of 155 m/s perpendicular to the Earths magnetic field of 5.00 X 10-5 T. If the bullet possesses a net charge of 18.5 X 10-9 C, by what distance will it be deflected from its path due to the Earths magnetic field after it has traveled 1.50 km?

Chapter: 20 Problem: 20.1

Physics: Principles with Applications 7
(a) What is the force per meter of length on a straight wire carrying a 6.40-A current when perpendicular to a 0.90-T uniform magnetic field? (b) What if the angle between the wire and field is 35.0?

Chapter: 20 Problem: 1

Physics: Principles with Applications 7
(I) (a) What is the force per meter of length on a straight wire carrying a 6.40-A current when perpendicular to a \(0.90-\mathrm{T}\) uniform magnetic field? (b) What if the angle between the wire and field is \(35.0^{\circ}\) ?

Chapter: 20 Problem: 20.2

Physics: Principles with Applications 7
How much current is flowing in a wire 4.80 m long if the maximum force on it is 0.625 N when placed in a uniform 0.0800-T field?

Chapter: 20 Problem: 2

Physics: Principles with Applications 7
How much current is flowing in a wire 4.80 m long if the maximum force on it is 0.625 N when placed in a uniform 0.0800-T field?

Chapter: 20 Problem: 20.3

Physics: Principles with Applications 7
A 240-m length of wire stretches between two towers and carries a 120-A current. Determine the magnitude of the force on the wire due to the Earths magnetic field of which makes an angle of 68 with the wire.

Chapter: 20 Problem: 3

Physics: Principles with Applications 7
(I) A 240-m length of wire stretches between two towers and carries a 120-A current. Determine the magnitude of the force on the wire due to the Earth's magnetic field of \(5.0 \times 10^{-5} \mathrm{~T}\) which makes an angle of \(68^{\circ}\) with the wire.

Chapter: 20 Problem: 20.4

Physics: Principles with Applications 7
A 2.6-m length of horizontal wire carries a 4.5-A current toward the south. The dip angle of the Earths magnetic field makes an angle of 41 to the wire. Estimate the magnitude of the magnetic force on the wire due to the Earths magnetic field of .

Chapter: 20 Problem: 4

Physics: Principles with Applications 7
(I) A 2.6-m length of horizontal wire carries a 4.5-A current toward the south. The dip angle of the Earth's magnetic field makes an angle of \(41^{\circ}\) to the wire. Estimate the magnitude of the magnetic force on the wire due to the Earth's magnetic field of \(5.5 \times 10^{-5} \mathrm{~T}\).

Chapter: 20 Problem: 20.5

Physics: Principles with Applications 7
The magnetic force per meter on a wire is measured to be only 45% of its maximum possible value. What is the angle between the wire and the magnetic field?

Chapter: 20 Problem: 5

Physics: Principles with Applications 7
The magnetic force per meter on a wire is measured to be only 45% of its maximum possible value. What is the angle between the wire and the magnetic field?

Chapter: 20 Problem: 20.6

Physics: Principles with Applications 7
The force on a wire carrying 6.45 A is a maximum of 1.28 N when placed between the pole faces of a magnet. If the pole faces are 55.5 cm in diameter, what is the approximate strength of the magnetic field?

Chapter: 20 Problem: 6

Physics: Principles with Applications 7
The force on a wire carrying 6.45 A is a maximum of 1.28 N when placed between the pole faces of a magnet. If the pole faces are 55.5 cm in diameter, what is the approximate strength of the magnetic field?

Chapter: 20 Problem: 20.7

Physics: Principles with Applications 7
The force on a wire is a maximum of when placed between the pole faces of a magnet. The current flows horizontally to the right and the magnetic field is vertical. The wire is observed to jump toward the observer when the current is turned on. (a) What type of magnetic pole is the top pole face? (b)

Chapter: 20 Problem: 7

Physics: Principles with Applications 7
(II) The force on a wire is a maximum of \(8.50 \times 10^{-2} \mathrm{~N}\) when placed between the pole faces of a magnet. The current flows horizontally to the right and the magnetic field is vertical. The wire is observed to "jump" toward the observer when the current is turned on. (a) What type

Chapter: 20 Problem: 20.8

Physics: Principles with Applications 7
Suppose a straight 1.00-mm-diameter copper wire could just float horizontally in air because of the force due to the Earths magnetic field which is horizontal, perpendicular to the wire, and of magnitude What current would the wire carry? Does the answer seem feasible? Explain briefly

Chapter: 20 Problem: 8

Physics: Principles with Applications 7
(II) Suppose a straight 1.00-mm-diameter copper wire could just "float" horizontally in air because of the force due to the Earth's magnetic field \(\overrightarrow{\mathbf{B}}\), which is horizontal, perpendicular to the wire, and of magnitude \(5.0 \times 10^{-5} \mathrm{~T}\). What current would t

Chapter: 20 Problem: 20.9

Physics: Principles with Applications 7
Determine the magnitude and direction of the force on an electron traveling horizontally to the east in a vertically upward magnetic field of strength 0.45 T

Chapter: 20 Problem: 9

Physics: Principles with Applications 7
(I) Determine the magnitude and direction of the force on an electron traveling \(7.75 \times 10^{5} \mathrm{~m} / \mathrm{s}\) horizontally to the east in a vertically upward magnetic field of strength 0.45 T. Equation

Chapter: 20 Problem: 20.10

Physics: Principles with Applications 7
An electron is projected vertically upward with a speed of into a uniform magnetic field of 0.640 T that is directed horizontally away from the observer. Describe the electrons path in this field.

Chapter: 20 Problem: 10

Physics: Principles with Applications 7
(I) An electron is projected vertically upward with a speed of \(1.70 \times 10^{6} \mathrm{~m} / \mathrm{s}\) into a uniform magnetic field of 0.640 T that is directed horizontally away from the observer. Describe the electron's path in this field.

Chapter: 20 Problem: 20.11

Physics: Principles with Applications 7
Alpha particles (charge , mass ) move at What magnetic field strength would be required to bend them into a circular path of radius

Chapter: 20 Problem: 11

Physics: Principles with Applications 7
(I) Alpha particles (charge \(q=+2 e\), mass \(m=6.6 \times 10^{-27} \mathrm{~kg}\) ) move at \(1.6 \times 10^{6} \mathrm{~m} / \mathrm{s}\). What magnetic field strength would be required to bend them into a circular path of radius \(r=0.14 \mathrm{~m}\) ?

Chapter: 20 Problem: 20.12

Physics: Principles with Applications 7
Find the direction of the force on a negative charge for each diagram shown in Fig. 2052, where (green) is the velocity of the charge and (blue) is the direction of the magnetic field. ( means the vector points inward. means it points outward, toward you.)

Chapter: 20 Problem: 12

Physics: Principles with Applications 7
(I) Find the direction of the force on a negative charge for each diagram shown in Fig. 2052, where \(\overrightarrow{v}\) (green) is the velocity of the charge and \(\overrightarrow{B}\) (blue) is the direction of the magnetic field. (\(\otimes\) means the vector points inward. \(\odot\) means it po

Chapter: 20 Problem: 20.13

Physics: Principles with Applications 7
Determine the direction of for each case in Fig. 2053, where represents the maximum magnetic force on a positively charged particle moving with velocity v B .

Chapter: 20 Problem: 13

Physics: Principles with Applications 7
(I) Determine the direction of \(\overrightarrow{\mathbf{B}}\) for each case in Fig. 20-53, where \(\overrightarrow{\mathbf{F}}\) represents the maximum magnetic force on a positively charged particle moving with velocity \(\overrightarrow{\mathbf{v}}\).

Chapter: 20 Problem: 20.14

Physics: Principles with Applications 7
What is the velocity of a beam of electrons that goes undeflected when moving perpendicular to an electric and to a magnetic field. and are also perpendicular to each other and have magnitudes and respectively. What is the radius of the electron orbit if the electric field is turned off?

Chapter: 20 Problem: 14

Physics: Principles with Applications 7
(II) What is the velocity of a beam of electrons that goes undeflected when moving perpendicular to an electric and to a magnetic field. \(\overrightarrow{\mathbf{E}}\) and \(\overrightarrow{\mathbf{B}}\) are also perpendicular to each other and have magnitudes \(7.7 \times 10^{3} \mathrm{~V} / \math

Chapter: 20 Problem: 20.15

Physics: Principles with Applications 7
A helium ion whose mass is is accelerated by a voltage of 3700 V. (a) What is its speed? (b) What will be its radius of curvature if it moves in a plane perpendicular to a uniform 0.340-T field? (c) What is its period of revolution?

Chapter: 20 Problem: 15

Physics: Principles with Applications 7
(II) A helium ion \((Q=+2 e)\) whose mass is \(6.6 \times 10^{-27} \mathrm{~kg}\) is accelerated by a voltage of 3700 V. (a) What is its speed? (b) What will be its radius of curvature if it moves in a plane perpendicular to a uniform 0.340-T field? (c) What is its period of revolution?

Chapter: 20 Problem: 20.16

Physics: Principles with Applications 7
For a particle of mass m and charge q moving in a circular path in a magnetic field B, (a) show that its kinetic energy is proportional to the square of the radius of curvature of its path. (b) Show that its angular momentum is around the center of the circle.

Chapter: 20 Problem: 16

Physics: Principles with Applications 7
(II) For a particle of mass \(m\) and charge \(q\) moving in a circular path in a magnetic field \(B,(a)\) show that its kinetic energy is proportional to \(r^{2}\), the square of the radius of curvature of its path. (b) Show that its angular momentum is \(L=q B r^{2}\), around the center of the circ

Chapter: 20 Problem: 20.17

Physics: Principles with Applications 7
A 1.5-MeV (kinetic energy) proton enters a 0.30-T field, in a plane perpendicular to the field. What is the radius of its path? See Section 174.

Chapter: 20 Problem: 17

Physics: Principles with Applications 7
A 1.5-MeV (kinetic energy) proton enters a 0.30-T field, in a plane perpendicular to the field. What is the radius of its path? See Section 174.

Chapter: 20 Problem: 20.18

Physics: Principles with Applications 7
An electron experiences the greatest force as it travels in a magnetic field when it is moving northward. The force is vertically upward and of magnitude What is the magnitude and direction of the magnetic field

Chapter: 20 Problem: 18

Physics: Principles with Applications 7
(II) An electron experiences the greatest force as it travels \(2.8 \times 10^{6} \mathrm{~m} / \mathrm{s}\) in a magnetic field when it is moving northward. The force is vertically upward and of magnitude \(6.2 \times 10^{-13} \mathrm{~N}\). What is the magnitude and direction of the magnetic field?

Chapter: 20 Problem: 20.19

Physics: Principles with Applications 7
A proton and an electron have the same kinetic energy upon entering a region of constant magnetic field. What is the ratio of the radii of their circular paths?

Chapter: 20 Problem: 19

Physics: Principles with Applications 7
A proton and an electron have the same kinetic energy upon entering a region of constant magnetic field. What is the ratio of the radii of their circular paths?

Chapter: 20 Problem: 20.20

Physics: Principles with Applications 7
A proton (mass ), a deuteron and an alpha particle are accelerated by the same potential difference V and then enter a uniform magnetic field where they move in circular paths perpendicular to Determine the radius of the paths for the deuteron and alpha particle in terms of that for the proton.

Chapter: 20 Problem: 20

Physics: Principles with Applications 7
(III) A proton (mass \(m_{\mathrm{p}}\) ), a deuteron \(\left(m=2 m_{\mathrm{p}}, Q=e\right)\), and an alpha particle \(\left(m=4 m_{\mathrm{p}}, Q=2 e\right)\) are accelerated by the same potential difference \(V\) and then enter a uniform magnetic field \(\overrightarrow{\mathbf{B}}\), where they m

Chapter: 20 Problem: 20.21

Physics: Principles with Applications 7
A 3.40-g bullet moves with a speed of perpendicular to the Earths magnetic field of If the bullet possesses a net charge of by what distance will it be deflected from its path due to the Earths magnetic field after it has traveled 1.50 km?

Chapter: 20 Problem: 21

Physics: Principles with Applications 7
(III) A 3.40-g bullet moves with a speed of 155 m/s perpendicular to the Earth's magnetic field of \(5.00 \times 10^{-5} \mathrm{~T}\). If the bullet possesses a net charge of \(18.5 \times 10^{-9} \mathrm{C}\), by what distance will it be deflected from its path due to the Earth's magnetic field aft

Chapter: 20 Problem: 20.22

Physics: Principles with Applications 7
A Hall probe, consisting of a thin rectangular slab of current-carrying material, is calibrated by placing it in a known magnetic field of magnitude 0.10 T. When the field is oriented normal to the slabs rectangular face, a Hall emf of 12 mV is measured across the slabs width. The probe is then place

Chapter: 20 Problem: 22

Physics: Principles with Applications 7
(III) A Hall probe, consisting of a thin rectangular slab of current-carrying material, is calibrated by placing it in a known magnetic field of magnitude 0.10 T. When the field is oriented normal to the slab's rectangular face, a Hall emf of 12 mV is measured across the slab's width. The probe is th

Chapter: 20 Problem: 20.23

Physics: Principles with Applications 7
The Hall effect can be used to measure blood flow rate because the blood contains ions that constitute an electric current. (a) Does the sign of the ions influence the emf? Explain. (b) Determine the flow velocity in an artery 3.3 mm in diameter if the measured emf across the width of the artery is 0

Chapter: 20 Problem: 23

Physics: Principles with Applications 7
The Hall effect can be used to measure blood flow rate because the blood contains ions that constitute an electric current. (a) Does the sign of the ions influence the emf? Explain. (b) Determine the flow velocity in an artery 3.3 mm in diameter if the measured emf across the width of the artery is 0

Chapter: 20 Problem: 20.24

Physics: Principles with Applications 7
A long copper strip 1.8 cm wide and 1.0 mm thick is placed in a 1.2-T magnetic field as in Fig. 2021a. When a steady current of 15 A passes through it, the Hall emf is measured to be Determine (a) the drift velocity of the electrons and (b) the density of free (conducting) electrons (number per unit

Chapter: 20 Problem: 24

Physics: Principles with Applications 7
(III) A long copper strip 1.8 cm wide and 1.0 mm thick is placed in a 1.2-T magnetic field as in Fig. 20-21a. When a steady current of 15 A passes through it, the Hall emf is measured to be \(1.02 \mu \mathrm{V}\). Determine (a) the drift velocity of the electrons and (b) the density of free (conduct

Chapter: 20 Problem: 20.25

Physics: Principles with Applications 7
Jumper cables used to start a stalled vehicle often carry a 65-A current. How strong is the magnetic field 4.5 cm from one cable? Compare to the Earths magnetic field

Chapter: 20 Problem: 25

Physics: Principles with Applications 7
(I) Jumper cables used to start a stalled vehicle often carry a 65 -A current. How strong is the magnetic field 4.5 cm from one cable? Compare to the Earth's magnetic field \(\left(5.0 \times 10^{-5} \mathrm{~T}\right)\).

Chapter: 20 Problem: 20.26

Physics: Principles with Applications 7
If an electric wire is allowed to produce a magnetic field no larger than that of the Earth at a distance of 12 cm from the wire, what is the maximum current the wire can carry?

Chapter: 20 Problem: 26

Physics: Principles with Applications 7
(I) If an electric wire is allowed to produce a magnetic field no larger than that of the Earth \(\left(0.50 \times 10^{-4} \mathrm{~T}\right)\) at a distance of 12 cm from the wire, what is the maximum current the wire can carry?

Chapter: 20 Problem: 20.27

Physics: Principles with Applications 7
Determine the magnitude and direction of the force between two parallel wires 25 m long and 4.0 cm apart, each carrying 25 A in the same direction.

Chapter: 20 Problem: 27

Physics: Principles with Applications 7
Determine the magnitude and direction of the force between two parallel wires 25 m long and 4.0 cm apart, each carrying 25 A in the same direction.

Chapter: 20 Problem: 20.28

Physics: Principles with Applications 7
A vertical straight wire carrying an upward 28-A current exerts an attractive force per unit length of on a second parallel wire 9.0 cm away. What current (magnitude and direction) flows in the second wire?

Chapter: 20 Problem: 28

Physics: Principles with Applications 7
(I) A vertical straight wire carrying an upward 28-A current exerts an attractive force per unit length of \(7.8 \times 10^{-4} \mathrm{~N} / \mathrm{m}\) on a second parallel wire 9.0 cm away. What current (magnitude and direction) flows in the second wire?

Chapter: 20 Problem: 20.29

Physics: Principles with Applications 7
In Fig. 2054, a long straight wire carries current I out of the page toward you. Indicate, with appropriate arrows, the direction and (relative) magnitude of at each of the points C, D, and E in the plane of the page.

Chapter: 20 Problem: 29

Physics: Principles with Applications 7
(II) In Fig. 20-54, a long straight wire carries current \(I\) out of the page toward you. Indicate, with appropriate arrows, the direction and (relative) magnitude of \(\overrightarrow{\mathbf{B}}\) at each of the points C, D, and E in the plane of the page.

Chapter: 20 Problem: 20.30

Physics: Principles with Applications 7
An experiment on the Earths magnetic field is being carried out 1.00 m from an electric cable. What is the maximum allowable current in the cable if the experiment is to be accurate to

Chapter: 20 Problem: 30

Physics: Principles with Applications 7
(II) An experiment on the Earth's magnetic field is being carried out 1.00 m from an electric cable. What is the maximum allowable current in the cable if the experiment is to be accurate to \(\pm 3.0 \%\) ? Equation Tr

Chapter: 20 Problem: 20.31

Physics: Principles with Applications 7
A rectangular loop of wire is placed next to a straight wire, as shown in Fig. 2055. There is a current of 3.5 A in both wires. Determine the magnitude and direction of the net force on the loop.

Chapter: 20 Problem: 31

Physics: Principles with Applications 7
(II) A rectangular loop of wire is placed next to a straight wire, as shown in Fig. 2055. There is a current of 3.5 A in both wires. Determine the magnitude and direction of the net force on the loop.

Chapter: 20 Problem: 20.32

Physics: Principles with Applications 7
A horizontal compass is placed 18 cm due south from a straight vertical wire carrying a 48-A current downward. In what direction does the compass needle point at this location? Assume the horizontal component of the Earths field at this point is and the magnetic declination is 0

Chapter: 20 Problem: 32

Physics: Principles with Applications 7
(II) A horizontal compass is placed 18 cm due south from a straight vertical wire carrying a 48 -A current downward. In what direction does the compass needle point at this location? Assume the horizontal component of the Earth's field at this point is \(0.45 \times 10^{-4} \mathrm{~T}\) and the magn

Chapter: 20 Problem: 20.33

Physics: Principles with Applications 7
A long horizontal wire carries 24.0 A of current due north. What is the net magnetic field 20.0 cm due west of the wire if the Earths field there points downward, 44 below the horizontal, and has magnitude

Chapter: 20 Problem: 33

Physics: Principles with Applications 7
(II) A long horizontal wire carries 24.0 A of current due north. What is the net magnetic field 20.0 cm due west of the wire if the Earth's field there points downward, \(44^{\circ}\) below the horizontal, and has magnitude \(5.0 \times 10^{-5} \mathrm{~T} ?\)

Chapter: 20 Problem: 20.34

Physics: Principles with Applications 7
A straight stream of protons passes a given point in space at a rate of What magnetic field do they produce 1.5 m from the beam?

Chapter: 20 Problem: 34

Physics: Principles with Applications 7
(II) A straight stream of protons passes a given point in space at a rate of \(2.5 \times 10^{9}\) protons/s. What magnetic field do they produce 1.5 m from the beam?