Question 1

What is the effective (rms) current value for an AC current with an amplitude of 10 A?

Accepted Answer

A) 28 A 
B) 3.1 A 
C) 7.1 A 
D) 14 A 
A) 28 A 
B) 3.1 A 
C) 7.1 A 
D) 14 A

Question 2

In an AC series circuit the inductive reactance is 50 W and the frequency is 100 Hz.What is the inductance in the circuit?

Accepted Answer

A) 80 mH 
B) 240 mH 
C) 500 mH 
D) 740 mH 
A) 80 mH 
B) 240 mH 
C) 500 mH 
D) 740 mH

Question 3

What is the phase angle of an AC series circuit that is constructed of a 10.0-W resistor along with 12.00 W inductive reactance and 7.00 W capacitive reactance?

Accepted Answer

A) 26.6$\degree$ 
B) 18.4$\degree$ 
C) 87.0$\degree$ 
D) 63.4$\degree$ 
A) 26.6$\degree$ 
B) 18.4$\degree$ 
C) 87.0$\degree$ 
D) 63.4$\degree$

Question 4

An AM radio tuning circuit has a coil with an inductance of 6.00 mH and a capacitor set at 7.50 * 10-6 mF.What frequency will it detect?

Accepted Answer

A) 550 kHz 
B) 750 kHz 
C) 1 060 kHz 
D) 1 520 kHz 
A) 550 kHz 
B) 750 kHz 
C) 1 060 kHz 
D) 1 520 kHz

Question 5

The electromagnetic radiation that causes tanning:

Accepted Answer

A) can produce cancer. 
B) rarely passes through glass windows. 
C) is absorbed by ozone. 
D) is all of the above. 
A) can produce cancer. 
B) rarely passes through glass windows. 
C) is absorbed by ozone. 
D) is all of the above.

Question 6

When a 50-mF capacitor is attached to an AC source, its capacitive reactance is 40 W.If instead a 100-mF capacitor is attached to the same source, what will be its capacitive reactance?

Accepted Answer

A) 80 O 
B) 57 O 
C) 28 O 
D) 20 O 
A) 80 O 
B) 57 O 
C) 28 O 
D) 20 O

Question 7

Temperature variation of different parts of a person's body can be detected by analyzing the emission pattern of which type of electromagnetic radiation?

Accepted Answer

A) microwave 
B) infrared 
C) ultraviolet 
D) x-rays 
A) microwave 
B) infrared 
C) ultraviolet 
D) x-rays

Question 8

A resistor and capacitor are connected in series with an applied AC voltage source.Separate voltmeter readings across the resistor and capacitor give values of 50 V and 75 V (rms), respectively.What is the effective (rms) voltage of the source?

Accepted Answer

A) 25 V 
B) 63 V 
C) 90 V 
D) 125 V 
A) 25 V 
B) 63 V 
C) 90 V 
D) 125 V

Question 9

Find the resonant frequency for a series RLC circuit where R = 20.0 W, C = 10.0 µF, and L = 4.0 mH.

Accepted Answer

A) 507 Hz 
B) 796 Hz 
C) 1.59 kHz 
D) 5.00 kHz 
A) 507 Hz 
B) 796 Hz 
C) 1.59 kHz 
D) 5.00 kHz

Question 10

What is the average power dissipation in a series RC circuit if R = 5.00 kW, C = 2.00 µF, and V = (170 V) cos 300t?

Accepted Answer

A) 2.60 W 
B) 2.74 W 
C) 28.2 W 
D) 157 W 
A) 2.60 W 
B) 2.74 W 
C) 28.2 W 
D) 157 W

Question 11

An AC series circuit contains a resistor of 20 W, an inductor of 30 mH and a variable capacitor.If the frequency of the applied voltage is 500 Hz, to what setting should the capacitor be set if resonance is achieved?

Accepted Answer

A) 0.8 µF 
B) 1.6 µF 
C) 2.4 µF 
D) 3.4 µF 
A) 0.8 µF 
B) 1.6 µF 
C) 2.4 µF 
D) 3.4 µF

Question 12

What is the wavelength of 100-MHz television EM waves? (c = 3 * 108 m/s)

Accepted Answer

A) 0.3 cm 
B) 3 m 
C) 9 km 
D) 10 m 
A) 0.3 cm 
B) 3 m 
C) 9 km 
D) 10 m

Question 13

A resistor, inductor and capacitor are connected in series, each with effective (rms) voltage of 65 V, 140 V and 80 V, respectively.If the resistor is rated at 24 W, what is the average power dissipated in the circuit?

Accepted Answer

A) 88 W 
B) 176 W 
C) 238 W 
D) 323 W 
A) 88 W 
B) 176 W 
C) 238 W 
D) 323 W

Question 14

A series RLC circuit in a radio is in resonance with AM 600 kHz.If the radio station is changed to AM 1 200 kHz, by what factor must the capacitance be multiplied to again achieve resonance?

Accepted Answer

A) 4 
B) 2 
C) 1/2 
D) 1/4 
A) 4 
B) 2 
C) 1/2 
D) 1/4

Question 15

When an RLC series circuit is in resonance, its impedance is:

Accepted Answer

A) zero. 
B) equal to its resistance. 
C) a maximum. 
D) p/2 W. 
A) zero. 
B) equal to its resistance. 
C) a maximum. 
D) p/2 W.

Question 16

Determine the amount of energy carried in l.0 m of a 3.5-mW He-Ne laser beam if the cross-sectional area of the beam is 5.0 * 10-6 m2.

Accepted Answer

A) 0.012 J 
B) 4.1 * 10-8 J 
C) 1.2 * 10-11 J 
D) 1.0 J 
A) 0.012 J 
B) 4.1 * 10-8 J 
C) 1.2 * 10-11 J 
D) 1.0 J

Question 17

A radar pulse returns 3.0 * 10-4 seconds after it is sent out, having been reflected by an object.What is the distance between the radar antenna and the object? (c = 3.00 * 108 m/s)

Accepted Answer

A) 9.0 * 104 m 
B) 4.5 * 104 m 
C) 6.0 * 104 m 
D) 1.0 * 104 m 
A) 9.0 * 104 m 
B) 4.5 * 104 m 
C) 6.0 * 104 m 
D) 1.0 * 104 m

Question 18

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 transmitted through a long-distance power line with a total resistance of 100 W.What is the rms current in the long-distance line?

Accepted Answer

A) 1.0 A 
B) 1.8 A 
C) 24 A 
D) 1 000 A 
A) 1.0 A 
B) 1.8 A 
C) 24 A 
D) 1 000 A

Question 19

A series circuit has equal values for resistance, capacitive reactance, and inductive reactance.The phase angle for this circuit is:

Accepted Answer

A) 60$\degree$. 
B) -60$\degree$. 
C) 180$\degree$. 
D) not given. 
A) 60$\degree$. 
B) -60$\degree$. 
C) 180$\degree$. 
D) not given.

Question 20

In the Doppler effect for electromagnetic waves, which of the following gives the greatest shift in frequency?

Accepted Answer

A) the source moving toward the non-moving observer at speed v 
B) the observer moving toward the non-moving source at speed v 
C) the source moving toward the approaching observer, both at speed v/2 
D) All of the above give the same shift. 
A) the source moving toward the non-moving observer at speed v 
B) the observer moving toward the non-moving source at speed v 
C) the source moving toward the approaching observer, both at speed v/2 
D) All of the above give the same shift.

Exam 21: Alternating Current Circuits and Electromagnetic Waves

What is the effective (rms) current value for an AC current with an amplitude of 10 A?

In an AC series circuit the inductive reactance is 50 W and the frequency is 100 Hz.What is the inductance in the circuit?

What is the phase angle of an AC series circuit that is constructed of a 10.0-W resistor along with 12.00 W inductive reactance and 7.00 W capacitive reactance?

An AM radio tuning circuit has a coil with an inductance of 6.00 mH and a capacitor set at 7.50 * 10-6 mF.What frequency will it detect?

The electromagnetic radiation that causes tanning:

When a 50-mF capacitor is attached to an AC source, its capacitive reactance is 40 W.If instead a 100-mF capacitor is attached to the same source, what will be its capacitive reactance?

Temperature variation of different parts of a person's body can be detected by analyzing the emission pattern of which type of electromagnetic radiation?

A resistor and capacitor are connected in series with an applied AC voltage source.Separate voltmeter readings across the resistor and capacitor give values of 50 V and 75 V (rms), respectively.What is the effective (rms) voltage of the source?

Find the resonant frequency for a series RLC circuit where R = 20.0 W, C = 10.0 µF, and L = 4.0 mH.

What is the average power dissipation in a series RC circuit if R = 5.00 kW, C = 2.00 µF, and V = (170 V) cos 300t?

An AC series circuit contains a resistor of 20 W, an inductor of 30 mH and a variable capacitor.If the frequency of the applied voltage is 500 Hz, to what setting should the capacitor be set if resonance is achieved?

What is the wavelength of 100-MHz television EM waves? (c = 3 * 108 m/s)

A resistor, inductor and capacitor are connected in series, each with effective (rms) voltage of 65 V, 140 V and 80 V, respectively.If the resistor is rated at 24 W, what is the average power dissipated in the circuit?

A series RLC circuit in a radio is in resonance with AM 600 kHz.If the radio station is changed to AM 1 200 kHz, by what factor must the capacitance be multiplied to again achieve resonance?

When an RLC series circuit is in resonance, its impedance is:

Determine the amount of energy carried in l.0 m of a 3.5-mW He-Ne laser beam if the cross-sectional area of the beam is 5.0 * 10-6 m2.

A radar pulse returns 3.0 * 10-4 seconds after it is sent out, having been reflected by an object.What is the distance between the radar antenna and the object? (c = 3.00 * 108 m/s)

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 transmitted through a long-distance power line with a total resistance of 100 W.What is the rms current in the long-distance line?

A series circuit has equal values for resistance, capacitive reactance, and inductive reactance.The phase angle for this circuit is:

In the Doppler effect for electromagnetic waves, which of the following gives the greatest shift in frequency?

Introduction

Motion in One Dimension

Vectors and Two-Dimensional Motion

The Laws of Motion

Energy

Momentum and Collisions

Rotational Motion and the Law of Gravity

Rotational Equilibrium and Rotational Dynamics

Solids and Fluids

Thermal Physics

Energy in Thermal Processes

The Laws of Thermodynamics

Vibrations and Waves

Sound

Electric Forces and Electric Fields

Electrical Energy and Capacitance

Current and Resistance

Direct-Current Circuits

Magnetism

Induced Voltages and Inductance

Reflection and Refraction of Light

Mirrors and Lenses

Wave Optics

Optical Instruments

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics

Nuclear Energy and Elementary Particles

Filters

An AM radio tuning circuit has a coil with an inductance of 6.00 mH and a capacitor set at 7.50 * 10^-6 mF.What frequency will it detect?

What is the wavelength of 100-MHz television EM waves? (c = 3 * 10⁸ m/s)

Determine the amount of energy carried in l.0 m of a 3.5-mW He-Ne laser beam if the cross-sectional area of the beam is 5.0 * 10^-6 m².

A radar pulse returns 3.0 * 10^-4 seconds after it is sent out, having been reflected by an object.What is the distance between the radar antenna and the object? (c = 3.00 * 10⁸ m/s)