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College Physics, | 8th Edition | ISBN: 9780495386933 | Authors: Raymond A. Serway Chris Vuille, Jerry S. Faughn

College Physics, 8th Edition solutions

Author: Raymond A. Serway Chris Vuille, Jerry S. Faughn
Publisher: Cengage Learning
ISBN: 9780495386933
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Chapter 21 Problems

Chapter: 21 Problem: 21.1

College Physics, 8
A sinusoidally varying voltage has a maximum value of 170 V. What is its rms value? (a) 240 V (b) 170 V (c) 120 V (d) 0 (e) 120 V

Chapter: 21 Problem: 21.2

College Physics, 8
When a particular inductor is connected to a source of sinusoidally varying voltage with constant amplitude and a frequency of 60.0 Hz, the rms current is 3.0 A. What is the rms current if the source frequency is doubled? (a) 12 A (b) 6.0 A (c) 4.2 A (d) 3.0 A (e) 1.5 A

Chapter: 21 Problem: 21.3

College Physics, 8
What is the rms voltage across a capacitor with capacitance (1.00/2p) mF carrying 1.00-mA rms AC current at 60.0 Hz? (a) 16.7 V (b) 13.2 V (c) 32.2 V (d) 0.560 V (e) 4.43 V

Chapter: 21 Problem: 21.4

College Physics, 8
Find the voltage across a (1.0/2p)-H inductor when it carries 2.0 A of rms current at 60.0 Hz. (a) 160 V (b) 140 V (c) 120 V (d) 95 V (e) 85 V

Chapter: 21 Problem: 21.5

College Physics, 8
A series RLC circuit contains a resistor of 20 _, a capacitor of 0.75 mF, and an inductor of 120 mH. If a sinusoidally varying rms voltage of 120 V is applied across this combination of elements, what is the rms current in the circuit when operating at its resonance frequency? (a) 2.4 A (b) 6.0 A (c)

Chapter: 21 Problem: 21.6

College Physics, 8
A 6.0-V battery is connected across the primary coil of a transformer having 50 turns. If the secondary coil of the transformer has 100 turns, what voltage appears across the secondary? (a) 24 V (b) 12 V (c) 6.0 V (d) 3.0 V (e) none of these

Chapter: 21 Problem: 21.7

College Physics, 8
An electromagnetic wave with a peak magnetic fi eld component of magnitude 1.5 _ 107 T has an associated peak electric fi eld component of what value? (a) 0.50 _ 1015 N/C (b) 2.0 _ 105 N/C (c) 2.2 _ 104 N/C (d) 45 N/C (e) 22 N/C

Chapter: 21 Problem: 21.8

College Physics, 8
An inductor and a resistor are connected in series across an AC generator, as shown in Figure MCQ21.8. Immediately after the switch is closed, which of the following statements is true? (a) The current is _V/R. (b) The voltage across the inductor is zero. (c) The current in the circuit is zero. (d) T

Chapter: 21 Problem: 21.9

College Physics, 8
A capacitor and a resistor are connected in series across an AC generator, as shown in Figure MCQ21.9. After the switch is closed, which of the following statements is true? (a) The voltage across the capacitor lags the current by 90. (b) The voltage across the resistor is out of phase with the curre

Chapter: 21 Problem: 21.10

College Physics, 8
A resistor, capacitor, and inductor are connected in series across an AC generator. Which of the following statements is false? (a) The instantaneous voltage across the capacitor lags the current by 90. (b) The instantaneous voltage across the inductor leads the current by 90. (c) The instantaneous v

Chapter: 21 Problem: 21.11

College Physics, 8
A resistor, capacitor, and inductor are connected in series across an AC generator. Which of the following statements is true? (a) All the power is lost in the inductor. (b) All the power is lost in the capacitor. (c) All the power is lost in the resistor. (d) Power is lost in all three elements. (e)

Chapter: 21 Problem: 21.12

College Physics, 8
If the voltage across a circuit element has its maximum value when the current in the circuit is zero, does it follow that (a) the circuit element is a resistor, (b) the circuit element is a capacitor, (c) the circuit element is an inductor, (d) the current and voltage are 90 out of phase, or (e) the

Chapter: 21 Problem: 21.13

College Physics, 8
What is the phase angle in a series RLC circuit at resonance? (a) 180 (b) 90 (c) 0 (d) 90 (e) 45

Chapter: 21 Problem: 21.14

College Physics, 8
A series RLC circuit contains a 20.0-_ resistor, a 0.75-mF capacitor, and a 120-mH inductor. If a sinusoidally varying rms voltage of 120 V at f _ 5.0 _ 102 Hz is applied across this combination of elements, what is the rms current in the circuit? (a) 2.3 A (b) 6.0 A (c) 10 A (d) 17 A (e) 4.8 A

Chapter: 21 Problem: 21.15

College Physics, 8
Before the advent of cable television and satellite dishes, homeowners either mounted a television antenna on the roof or used rabbit ears atop their sets. (See Fig. CQ21.1.) Certain orientations of the receiving antenna on a television set gave better reception than others. Furthermore, the best ori

Chapter: 21 Problem: 21.16

College Physics, 8
What is the impedance of an RLC circuit at the resonance frequency?

Chapter: 21 Problem: 21.17

College Physics, 8
Receiving radio antennas can be in the form of conducting lines or loops. What should the orientation of each of these antennas be relative to a broadcasting antenna that is vertical?

Chapter: 21 Problem: 21.18

College Physics, 8
If the fundamental source of a sound wave is a vibrating object, what is the fundamental source of an electromagnetic wave?

Chapter: 21 Problem: 21.19

College Physics, 8
In radio transmission a radio wave serves as a carrier wave, and the sound signal is superimposed on the carrier wave. In amplitude modulation (AM) radio, the amplitude of the carrier wave varies according to the sound wave. The U.S. Navy sometimes uses fl ashing lights to send Morse code between nei

Chapter: 21 Problem: 21.20

College Physics, 8
When light (or other electromagnetic radiation) travels across a given region, what is it that oscillates? What is it that is transported?

Chapter: 21 Problem: 21.21

College Physics, 8
In space sailing, which is a proposed alternative for transport to the planets, a spacecraft carries a very large sail. Sunlight striking the sail exerts a force, accelerating the spacecraft. Should the sail be absorptive or refl ective to be most effective?

Chapter: 21 Problem: 21.22

College Physics, 8
How can the average value of an alternating current be zero, yet the square root of the average squared value not be zero?

Chapter: 21 Problem: 21.23

College Physics, 8
Suppose a creature from another planet had eyes that were sensitive to infrared radiation. Describe what it would see if it looked around the room that you are now in. That is, what would be bright and what would be dim?

Chapter: 21 Problem: 21.24

College Physics, 8
Why should an infrared photograph of a person look different from a photograph taken using visible light?

Chapter: 21 Problem: 21.25

College Physics, 8
Does a wire connected to a battery emit an electromagnetic wave?

Chapter: 21 Problem: 21.26

College Physics, 8
If a high-frequency current is passed through a solenoid containing a metallic core, the core becomes warm due to induction. Explain why the temperature of the material rises in this situation.

Chapter: 21 Problem: 21.27

College Physics, 8
If the resistance in an RLC circuit remains the same, but the capacitance and inductance are each doubled, how will the resonance frequency change?

Chapter: 21 Problem: 21.28

College Physics, 8
Why is the sum of the maximum voltages across each of the elements in a series RLC circuit usually greater than the maximum applied voltage? Doesnt this violate Kirchhoffs loop rule?

Chapter: 21 Problem: 21.29

College Physics, 8
What is the advantage of transmitting power at high voltages?

Chapter: 21 Problem: 21.30

College Physics, 8
When an AC generator is connected across a 12.0-_ resistor, the rms current in the resistor is 8.00 A. Find (a) the rms voltage across the resistor, (b) the peak voltage of the generator, (c) the maximum current in the resistor, and (d) the average power delivered to the resistor.

Chapter: 21 Problem: 21.31

College Physics, 8
A certain lightbulb is rated at 60.0 W when operating at an rms voltage of 1.20 _ 102 V. (a) What is the peak voltage applied across the bulb? (b) What is the resistance of the bulb? (c) Does a 1.00 _ 102 W bulb have greater or less resistance than a 60.0-W bulb? Explain.

Chapter: 21 Problem: 21.32

College Physics, 8
An AC power supply that produces a maximum voltage of _Vmax _ 100 V is connected to a 24.0-_ resistor. The current and the resistor voltage are respectively measured with an ideal AC ammeter and an ideal AC voltmeter, as shown in Figure P21.3. What does each meter read? Note that an ideal ammeter has

Chapter: 21 Problem: 21.33

College Physics, 8
Figure P21.4 shows three lamps connected to a 120-V AC (rms) household supply voltage. Lamps 1 and 2 have 150-W bulbs; lamp 3 has a 100-W bulb. Find the rms current and the resistance of each bulb. FIGURE P21.4 120 V 1 2 3

Chapter: 21 Problem: 21.34

College Physics, 8
An audio amplifi er, represented by the AC source and the resistor R in Figure P21.5, delivers alternating voltages at audio frequencies to the speaker. If the source puts out an alternating voltage of 15.0 V (rms), the resistance R is 8.20 _, and the speaker is equivalent to a resistance of 10.4 _,

Chapter: 21 Problem: 21.35

College Physics, 8
The output voltage of an AC generator is given by _v _ (170 V) sin (60pt). The generator is connected across a 20.0-_ resistor. By inspection, what are the (a) maximum voltage and (b) frequency? Find the (c) rms voltage across the resistor, (d) rms current in the resistor, (e) maximum current in the

Chapter: 21 Problem: 21.36

College Physics, 8
Show that the SI unit of capacitive reactance Xc is the ohm.

Chapter: 21 Problem: 21.37

College Physics, 8
What is the maximum current delivered to a circuit containing a 2.20-mF capacitor when it is connected across (a) a North American outlet having _Vrms _ 120 V and f _ 60.0 Hz and (b) a European outlet having _Vrms _ 240 V and f _ 50.0 Hz?

Chapter: 21 Problem: 21.38

College Physics, 8
When a 4.0-mF capacitor is connected to a generator whose rms output is 30 V, the current in the circuit is observed to be 0.30 A. What is the frequency of the source?

Chapter: 21 Problem: 21.39

College Physics, 8
An AC generator with an output rms voltage of 36.0 V at a frequency of 60.0 Hz is connected across a 12.0-mF capacitor. Find the (a) capacitive reactance, (b) rms current, and (c) maximum current in the circuit. (d) Does the capacitor have its maximum charge when the current takes its maximum value?

Chapter: 21 Problem: 21.40

College Physics, 8
What must be the capacitance of a capacitor inserted in a 60-Hz circuit in series with a generator of 170-V maximum output voltage to produce an rms current output of 0.75 A?

Chapter: 21 Problem: 21.41

College Physics, 8
A generator delivers an AC voltage of the form _v _ (98.0 V) sin (80pt) to a capacitor. The maximum current in the circuit is 0.500 A. Find the (a) rms voltage of the generator, (b) frequency of the generator, (c) rms current, (d) reactance, and (e) value of the capacitance.

Chapter: 21 Problem: 21.42

College Physics, 8
Show that the inductive reactance XL has SI units of ohms.

Chapter: 21 Problem: 21.43

College Physics, 8
An AC generator has an output rms voltage of 78.0 V at a frequency of 80.0 Hz. If the generator is connected across a 25.0-mH inductor, fi nd the (a) inductive reactance, (b) rms current, and (c) maximum current in the circuit.

Chapter: 21 Problem: 21.44

College Physics, 8
An inductor is connected to an AC power supply having a maximum output voltage of 4.00 V at a frequency of 300.0 Hz. What inductance is needed to keep the rms current less than 2.00 mA?

Chapter: 21 Problem: 21.45

College Physics, 8
The output voltage of an AC generator is given by _v _ (1.20 _ 102 V) sin (30pt). The generator is connected across a 0.500-H inductor. Find the (a) frequency of the generator, (b) rms voltage across the inductor, (c) inductive reactance, (d) rms current in the inductor, (e) maximum current in the in

Chapter: 21 Problem: 21.46

College Physics, 8
Determine the maximum magnetic fl ux through an inductor connected to a standard outlet (_Vrms _ 120 V, f _ 60.0 Hz). RLC

Chapter: 21 Problem: 21.47

College Physics, 8
A sinusoidal voltage _v _ (80.0 V) sin (150t) is applied to a series RLC circuit with L _ 80.0 mH, C _ 125.0 mF, and R _ 40.0 _. (a) What is the impedance of the circuit? (b) What is the maximum current in the circuit?

Chapter: 21 Problem: 21.48

College Physics, 8
A 40.0-mF capacitor is connected to a 50.0-_ resistor and a generator whose rms output is 30.0 V at 60.0 Hz. Find (a) the rms current in the circuit, (b) the rms voltage drop across the resistor, (c) the rms voltage drop across the capacitor, and (d) the phase angle for the circuit.

Chapter: 21 Problem: 21.49

College Physics, 8
An inductor (L _ 400 mH), a capacitor (C _ 4.43 mF), and a resistor (R _ 500 _) are connected in series. A 50.0-Hz AC generator connected in series to these elements produces a maximum current of 250 mA in the circuit. (a) Calculate the required maximum voltage _Vmax. (b) Determine the phase angle by

Chapter: 21 Problem: 21.50

College Physics, 8
A resistor (R _ 9.00 _ 102 _), a capacitor (C _ 0.250 mF), and an inductor (L _ 2.50 H) are connected in series across a 2.40 _ 102-Hz AC source for which _Vmax _ 1.40 _ 102 V. Calculate (a) the impedance of the circuit, (b) the maximum current delivered by the source, and (c) the phase angle between

Chapter: 21 Problem: 21.51

College Physics, 8
A 50.0-_ resistor, a 0.100-H inductor, and a 10.0-mF capacitor are connected in series to a 60.0-Hz source. The rms current in the circuit is 2.75 A. Find the rms voltages across (a) the resistor, (b) the inductor, (c) the capacitor, and (d) the RLC combination. (e) Sketch the phasor diagram for this

Chapter: 21 Problem: 21.52

College Physics, 8
A 60.0-_ resistor, a 3.00-mF capacitor, and a 0.400-H inductor are connected in series to a 90.0-V (rms), 60.0-Hz source. Find (a) the voltage drop across the LC combination and (b) the voltage drop across the RC combination.

Chapter: 21 Problem: 21.53

College Physics, 8
An AC source operating at 60 Hz with a maximum voltage of 170 V is connected in series with a resistor (R _ 1.2 k_) and an inductor (L _ 2.8 H). (a) What is the maximum value of the current in the circuit? (b) What are the maximum values of the potential difference across the resistor and the inducto

Chapter: 21 Problem: 21.54

College Physics, 8
A person is working near the secondary of a transformer, as shown in Figure P21.25. The primary voltage is 120 V (rms) at 60.0 Hz. The capacitance Cs, which is the stray capacitance between the hand and the secondary winding, is 20.0 pF. Assuming the person has a body resistance to ground of Rb _ 50.

Chapter: 21 Problem: 21.55

College Physics, 8
A series RLC circuit contains the following components: R _ 1.50 _ 102 _, L _ 2.50 _ 102 mH, C _ 2.00 mF, and a generator with _Vmax _ 2.10 _ 102 V operating at 50.0 Hz. Calculate the (a) inductive reactance, (b) capacitive reactance, (c) impedance, (d) maximum current, and (e) phase angle between th

Chapter: 21 Problem: 21.56

College Physics, 8
Consider the RLC circuit in Problem 21.27. When the voltage across the resistor is a maximum, what are the individual voltages across the capacitor and inductor? Explain.

Chapter: 21 Problem: 21.57

College Physics, 8
An AC source with a maximum voltage of 150 V and f _ 50.0 Hz is connected between points a and d in Figure P21.29. Calculate the rms voltages between points (a) a and b, (b) b and c, (c) c and d, and (d) b and d. FIGURE P21.25 Rb Cs 5 000 V Transformer

Chapter: 21 Problem: 21.58

College Physics, 8
A 60.0-_ resistor is connected in series with a 30.0-mF capacitor and a generator having a maximum voltage of 1.20 _ 102 V and operating at 60.0 Hz. Find the (a) capacitive reactance of the circuit, (b) impedance of the circuit, and (c) maximum current in the circuit. FIGURE P21.29 a b c d 40.0 _ 185

Chapter: 21 Problem: 21.59

College Physics, 8
An AC source operating at 60 Hz with a maximum voltage of 170 V is connected in series with a resistor (R _ 1.2 k_) and a capacitor (C _ 2.5 mF). (a) What is the maximum value of the current in the circuit? (b) What are the maximum values of the potential difference across the resistor and the capaci

Chapter: 21 Problem: 21.60

College Physics, 8
A multimeter in an RL circuit records an rms current of 0.500 A and a 60.0-Hz rms generator voltage of 104 V. A wattmeter shows that the average power delivered to the resistor is 10.0 W. Determine (a) the impedance in the circuit, (b) the resistance R, and (c) the inductance L.

Chapter: 21 Problem: 21.61

College Physics, 8
An AC voltage of the form _v _ (90.0 V) sin (350t) is applied to a series RLC circuit. If R _ 50.0 _, C _ 25.0 mF, and L _ 0.200 H, fi nd the (a) impedance of the circuit, (b) rms current in the circuit, and (c) average power delivered to the circuit.

Chapter: 21 Problem: 21.62

College Physics, 8
Calculate the average power delivered to the circuit described in Problem 21.

Chapter: 21 Problem: 21.63

College Physics, 8
A series RLC circuit has a resistance of 22.0 _ and an impedance of 80.0 _. If the rms voltage applied to the circuit is 160 V, what average power is delivered to the circuit?

Chapter: 21 Problem: 21.64

College Physics, 8
An inductor and a resistor are connected in series. When connected to a 60-Hz, 90-V (rms) source, the voltage drop across the resistor is found to be 50 V (rms) and the power delivered to the circuit is 14 W. Find (a) the value of the resistance and (b) the value of the inductance.

Chapter: 21 Problem: 21.65

College Physics, 8
Consider a series RLC circuit with R _ 25 _, L _ 6.0 mH, and C _ 25 mF. The circuit is connected to a 10-V (rms), 600-Hz AC source. (a) Is the sum of the voltage drops across R, L, and C equal to 10 V (rms)? (b) Which is greatest, the power delivered to the resistor, to the capacitor, or to the induc

Chapter: 21 Problem: 21.66

College Physics, 8
A resonant circuit in a radio receiver is tuned to a certain station when the inductor has a value of 3.00 mH and the capacitor has a value of 2.50 pF. The resistance of the circuit is 12 _. (a) Find the frequency of the radio station. (b) Is there any information given in the problem that is not nee

Chapter: 21 Problem: 21.67

College Physics, 8
The LC circuit of a radar transmitter oscillates at 9.00 GHz. (a) What inductance will resonate with a 2.00-pF capacitor at this frequency? (b) What is the inductive reactance of the circuit at this frequency?

Chapter: 21 Problem: 21.68

College Physics, 8
The AM band extends from approximately 500 kHz to 1 600 kHz. If a 2.0-mH inductor is used in a tuning circuit for a radio, what are the extremes that a capacitor must reach to cover the complete band of frequencies?

Chapter: 21 Problem: 21.69

College Physics, 8
Consider a series RLC circuit with R _ 15 _, L _ 200 mH, C _ 75 mF, and a maximum voltage of 150 V. (a) What is the impedance of the circuit at resonance? (b) What is the resonance frequency of the circuit? (c) When will the current be greatest: at resonance, at 10% below the resonant frequency, or a

Chapter: 21 Problem: 21.70

College Physics, 8
A 10.0-_ resistor, a 10.0-mH inductor, and a 100-mF capacitor are connected in series to a 50.0-V (rms) source having variable frequency. Find the energy delivered to the circuit during one period if the operating frequency is twice the resonance frequency.

Chapter: 21 Problem: 21.71

College Physics, 8
A series circuit contains a 3.00-H inductor, a 3.00-mF capacitor, and a 30.0-_ resistor connected to a 120-V (rms) source of variable frequency. Find the power delivered to the circuit when the frequency of the source is (a) the resonance frequency, (b) one-half the resonance frequency, (c) one-fourt

Chapter: 21 Problem: 21.72

College Physics, 8
The primary coil of a transformer has N1 _ 250 turns, and its secondary coil has N2 _ 1 500 turns. If the input voltage across the primary coil is _v _ (170 V) sin vt, what rms voltage is developed across the secondary coil?

Chapter: 21 Problem: 21.73

College Physics, 8
A step-down transformer is used for recharging the batteries of portable devices. The turns ratio N2/N1 for a particular transformer used in a CD player is 1:13. When used with 120-V (rms) household service, the transformer draws an rms current of 250 mA. Find the (a) rms output voltage of the transf

Chapter: 21 Problem: 21.74

College Physics, 8
An AC power generator produces 50 A (rms) at 3 600 V. The voltage is stepped up to 100 000 V by an ideal transformer, and the energy is transmitted through a longdistance power line that has a resistance of 100 _. What percentage of the power delivered by the generator is dissipated as heat in the po

Chapter: 21 Problem: 21.75

College Physics, 8
A transformer is to be used to provide power for a computer disk drive that needs 6.0 V (rms) instead of the 120 V (rms) from the wall outlet. The number of turns in the primary is 400, and it delivers 500 mA (the secondary current) at an output voltage of 6.0 V (rms). (a) Should the transformer have

Chapter: 21 Problem: 21.76

College Physics, 8
A transformer on a pole near a factory steps the voltage down from 3 600 V (rms) to 120 V (rms). The transformer is to deliver 1 000 kW to the factory at 90% effi ciency. Find (a) the power delivered to the primary, (b) the current in the primary, and (c) the current in the secondary.

Chapter: 21 Problem: 21.77

College Physics, 8
A transmission line that has a resistance per unit length of 4.50 _ 104 _/m is to be used to transmit 5.00 MW over 400 miles (6.44 _ 105 m). The output voltage of the generator is 4.50 kV (rms). (a) What is the line loss if a transformer is used to step up the voltage to 500 kV (rms)? (b) What fracti

Chapter: 21 Problem: 21.78

College Physics, 8
The U.S. Navy has long proposed the construction of extremely low frequency (ELF waves) communications systems; such waves could penetrate the oceans to reach distant submarines. Calculate the length of a quarterwavelength antenna for a transmitter generating ELF waves of frequency 75 Hz. How practic

Chapter: 21 Problem: 21.79

College Physics, 8
(a) The distance to Polaris, the North Star, is approximately 6.44 _ 1018 m. If Polaris were to burn out today, how many years would it take to see it disappear? (b) How long does it take sunlight to reach Earth? (c) How long does it take a microwave signal to travel from Earth to the Moon and back?

Chapter: 21 Problem: 21.80

College Physics, 8
An electromagnetic wave in free space has an electric fi eld of amplitude 330 V/m. Find the amplitude of the corresponding magnetic fi eld.

Chapter: 21 Problem: 21.81

College Physics, 8
Experimenters at the National Institute of Standards and Technology have made precise measurements of the speed of light using the fact that, in vacuum, the speed of electromagnetic waves is c 5 1/!m0P0, where the constants m0 _ 4p _ 107 N _ s2/C2 and P0 _ 8.854 _ 1012 C2/N _ m2. What value (to four

Chapter: 21 Problem: 21.82

College Physics, 8
Oxygenated hemoglobin absorbs weakly in the red (hence its red color) and strongly in the near infrared, whereas deoxygenated hemoglobin has the opposite absorption. This fact is used in a pulse oximeter to measure oxygen saturation in arterial blood. The device clips onto the end of a persons fi nge

Chapter: 21 Problem: 21.83

College Physics, 8
Operation of the pulse oximeter (see previous problem). The transmission of light energy as it passes through a solution of light-absorbing molecules is described by the BeerLambert law I 5 I0102PCL or log10 a I I0 b 5 2PCL which gives the decrease in intensity I in terms of the distance L the light

Chapter: 21 Problem: 21.84

College Physics, 8
The Sun delivers an average power of 1 340 W/m2 to the top of Earths atmosphere. Find the magnitudes of E S max and B S max for the electromagnetic waves at the top of the atmosphere.

Chapter: 21 Problem: 21.85

College Physics, 8
A laser beam is used to levitate a metal disk against the force of Earths gravity. (a) Derive an equation giving the required intensity of light, I, in terms of the mass m of the disk, the gravitational acceleration g, the speed of light c, and the cross-sectional area of the disk A. Assume the disk

Chapter: 21 Problem: 21.86

College Physics, 8
A microwave oven is powered by an electron tube called a magnetron that generates electromagnetic waves of frequency 2.45 GHz. The microwaves enter the oven and are refl ected by the walls. The standing-wave pattern produced in the oven can cook food unevenly, with hot spots in the food at antinodes

Chapter: 21 Problem: 21.87

College Physics, 8
Assume the solar radiation incident on Earth is 1 340 W/m2 (at the top of Earths atmosphere). Calculate the total power radiated by the Sun, taking the average separation between Earth and the Sun to be 1.49 _ 1011 m.

Chapter: 21 Problem: 21.88

College Physics, 8
The eye is most sensitive to light of wavelength 5.50 _ 107 m, which is in the greenyellow region of the visible electromagnetic spectrum. What is the frequency of this light?

Chapter: 21 Problem: 21.89

College Physics, 8
A diathermy machine, used in physiotherapy, generates electromagnetic radiation that gives the effect of deep heat when absorbed in tissue. One assigned frequency for diathermy is 27.33 MHz. What is the wavelength of this radiation?

Chapter: 21 Problem: 21.90

College Physics, 8
What are the wavelength ranges in (a) the AM radio band (5401 600 kHz) and (b) the FM radio band (88 108 MHz)?

Chapter: 21 Problem: 21.91

College Physics, 8
An important news announcement is transmitted by radio waves to people who are 100 km away, sitting next to their radios, and by sound waves to people sitting across the newsroom, 3.0 m from the newscaster. Who receives the news fi rst? Explain. Take the speed of sound in air to be 343 m/s.

Chapter: 21 Problem: 21.92

College Physics, 8
Infrared spectra are used by chemists to help identify an unknown substance. Atoms in a molecule that are bound together by a particular bond vibrate at a predictable frequency, and light at that frequency is absorbed strongly by the atom. In the case of the CwO double bond, for example, the oxygen a

Chapter: 21 Problem: 21.93

College Physics, 8
A spaceship is approaching a space station at a speed of 1.8 _ 105 m/s. The space station has a beacon that emits green light with a frequency of 6.0 _ 1014 Hz. What is the frequency of the beacon observed on the spaceship? What is the change in frequency? (Carry fi ve digits in these calculations.)

Chapter: 21 Problem: 21.94

College Physics, 8
While driving at a constant speed of 80 km/h, you are passed by a car traveling at 120 km/h. If the frequency of light emitted by the taillights of the car that passes you is 4.3 _ 1014 Hz, what frequency will you observe? What is the change in frequency?

Chapter: 21 Problem: 21.95

College Physics, 8
A speeder tries to explain to the police that the yellow warning lights on the side of the road looked green to her because of the Doppler shift. How fast would she have been traveling if yellow light of wavelength 580 nm had been shifted to green with a wavelength of 560 nm? Note: For speeds less th

Chapter: 21 Problem: 21.96

College Physics, 8
A 50.0-_ resistor is connected in series with a 15.0-mF capacitor and a 60.0-Hz, 1.20 _ 102-V (rms) source. Find the (a) impedance of the circuit and (b) rms current in the circuit. (c) What is the value of the inductor that must be inserted in the circuit to reduce the current to onehalf that found

Chapter: 21 Problem: 21.97

College Physics, 8
The intensity of solar radiation at the top of Earths atmosphere is 1 340 W/m3. Assuming 60% of the incoming solar energy reaches Earths surface and assuming you absorb 50% of the incident energy, make an order-ofmagnitude estimate of the amount of solar energy you absorb in a 60-minute sunbath.

Chapter: 21 Problem: 21.98

College Physics, 8
A 200-_ resistor is connected in series with a 5.0-mF capacitor and a 60-Hz, 120-V rms line. If electrical energy costs $0.080/kWh, how much does it cost to leave this circuit connected for 24 h?

Chapter: 21 Problem: 21.99

College Physics, 8
A series RLC circuit has a resonance frequency of 2 000/p Hz. When it is operating at a frequency of v _ v0, XL _ 12 _ and XC _ 8.0 _. Calculate the values of L and C for the circuit.

Chapter: 21 Problem: 21.100

College Physics, 8
As a way of determining the inductance of a coil used in a research project, a student fi rst connects the coil to a 12.0-V battery and measures a current of 0.630 A. The student then connects the coil to a 24.0-V (rms), 60.0-Hz generator and measures an rms current of 0.570 A. What is the inductance

Chapter: 21 Problem: 21.101

College Physics, 8
(a) What capacitance will resonate with a one-turn loop of inductance 400 pH to give a radar wave of wavelength 3.0 cm? (b) If the capacitor has square parallel plates separated by 1.0 mm of air, what should the edge length of the plates be? (c) What is the common reactance of the loop and capacitor

Chapter: 21 Problem: 21.102

College Physics, 8
A dish antenna with a diameter of 20.0 m receives (at normal incidence) a radio signal from a distant source, as shown in Figure P21.73. The radio signal is a continuous sinusoidal wave with amplitude Emax _ 0.20 mV/m. Assume the antenna absorbs all the radiation that falls on the dish. (a) What is t

Chapter: 21 Problem: 21.103

College Physics, 8
A particular inductor has appreciable resistance. When the inductor is connected to a 12-V battery, the current in the inductor is 3.0 A. When it is connected to an AC source with an rms output of 12 V and a frequency of 60 Hz, the current drops to 2.0 A. What are (a) the impedance at 60 Hz and (b) t

Chapter: 21 Problem: 21.104

College Physics, 8
One possible means of achieving space fl ight is to place a perfectly refl ecting aluminized sheet into Earths orbit and to use the light from the Sun to push this solar sail. Suppose such a sail, of area 6.00 _ 104 m2 and mass 6 000 kg, is placed in orbit facing the Sun. (a) What force is exerted on

Chapter: 21 Problem: 21.105

College Physics, 8
The U.S. Food and Drug Administration limits the radiation leakage of microwave ovens to no more than 5.0 mW/cm2 at a distance of 2.0 in. A typical cell phone, which also transmits microwaves, has a peak output power of about 2.0 W. (a) Approximating the cell phone as a point source, calculate the ra

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