Question 1

The average power dissipated in an RLC series circuit at resonance is dependent upon

Accepted Answer

A)  the frequency. 
B)  the capacitive reactance. 
C)  the inductive reactance. 
D)  the resistance. 
A)  the frequency. 
B)  the capacitive reactance. 
C)  the inductive reactance. 
D)  the resistance. D

Question 2

An RLC series circuit has a 400 Ω resistance, a 2.5 mH inductor, and a capacitor. If the resonant frequency is 30 kHz, what is the capacitive reactance at resonance?

Accepted Answer

A)  4.0 × 102 Ω 
B)  6.2 × 102 Ω 
C)  4.7 × 102 Ω 
D)  71 Ω 
E)  0.00 
A)  4.0 × 102 Ω 
B)  6.2 × 102 Ω 
C)  4.7 × 102 Ω 
D)  71 Ω 
E)  0.00 C

Question 3

A series RLC circuit has resistance 200 Ω, inductance 0.200 H, and capacitance 0.500 μF. If the circuit is at resonance with a 120 V rms source, what is the average power dissipated?

Accepted Answer

A)  144 W 
B)  120 W 
C)  77.0 W 
D)  72.0 W 
E)  100 W 
A)  144 W 
B)  120 W 
C)  77.0 W 
D)  72.0 W 
E)  100 W D

Question 4

The inductive reactance of an RLC circuit is 36 Ω. If the frequency is doubled, what is the new inductive reactance?

Accepted Answer

A)  72 Ω 
B)  36 Ω 
C)  19 Ω 
D)  6.0 Ω 
E)  3.0 Ω 
A)  72 Ω 
B)  36 Ω 
C)  19 Ω 
D)  6.0 Ω 
E)  3.0 Ω

Question 5

As the ac frequency in an RLC circuit is increased to very high values, which of the contributions to the impedance dominates?

Accepted Answer

A)  the capacitive reactance 
B)  the inductive reactance 
C)  the resistance 
D)  the combined capacitive reactance and the resistance 
E)  More information is needed. 
A)  the capacitive reactance 
B)  the inductive reactance 
C)  the resistance 
D)  the combined capacitive reactance and the resistance 
E)  More information is needed.

Question 6

An ac circuit consists of a 220 mH inductor in series with a 75 kΩ resistor and a sinusoidal source with an rms voltage of 12 V. At what frequency will the rms voltage across the resistor be equal to that across the inductor?

Accepted Answer

A)  114 kHz 
B)  5.5 kHz 
C)  54 kHz 
D)  18 kHz 
A)  114 kHz 
B)  5.5 kHz 
C)  54 kHz 
D)  18 kHz

Question 7

In an RLC ac circuit the current in the inductor and the current in the resistor are

Accepted Answer

A)  out of phase by 90° with the current in the inductor leading. 
B)  out of phase by 90° with the current in the resistor leading. 
C)  in phase with each other. 
D)  out of phase by an amount proportional to frequency. 
E)  out of phase by an amount inversely proportional to frequency. 
A)  out of phase by 90° with the current in the inductor leading. 
B)  out of phase by 90° with the current in the resistor leading. 
C)  in phase with each other. 
D)  out of phase by an amount proportional to frequency. 
E)  out of phase by an amount inversely proportional to frequency.

Question 8

What is the peak (maximum) power dissipated by a 150 W light bulb attached to a 120 V rms ac line?

Accepted Answer

A)  300 W 
B)  212 W 
C)  150 W 
D)  106 W 
E)  75.0 W 
A)  300 W 
B)  212 W 
C)  150 W 
D)  106 W 
E)  75.0 W

Question 9

An ac circuit consists of a 220 mH inductor in series with a 25 pF capacitor and a sinusoidal ac generator with an rms voltage of 12 V. If the frequency of the generator is 55 kHz, what will the rms voltage across the capacitor be?

Accepted Answer

A)  5.4 V 
B)  35 V 
C)  6.6 V 
D)  11.80 V 
A)  5.4 V 
B)  35 V 
C)  6.6 V 
D)  11.80 V

Question 10

An RLC series circuit has a 22 Ω resistor, a 3.0 H inductor, and a capacitor. What capacitance would result in resonance at 60 Hz?

Accepted Answer

A)  55 mF 
B)  0.33 F 
C)  65 μF 
D)  15 mF 
E)  2.3 μF 
A)  55 mF 
B)  0.33 F 
C)  65 μF 
D)  15 mF 
E)  2.3 μF

Question 11

For an ideal inductor in an ac circuit, how much energy is stored in the inductor at the instant when the current is zero?

Accepted Answer

A)  maximum 
B)  half 
C)  0.707 maximum 
D)  zero 
A)  maximum 
B)  half 
C)  0.707 maximum 
D)  zero

Question 12

What is the capacitance of a capacitor with a reactance of 20.0 Ω at a frequency of 60.0 Hz?

Accepted Answer

A)  50.0 mF 
B)  50.0 μF 
C)  133 mF 
D)  133 μF 
E)  833 μF 
A)  50.0 mF 
B)  50.0 μF 
C)  133 mF 
D)  133 μF 
E)  833 μF

Question 13

A lightbulb is connected to a 120 V (rms), 60 Hz source. How many times per second does the current reverse directions?

Accepted Answer

A)  60 
B)  130 
C)  120 
D)  30 
A)  60 
B)  130 
C)  120 
D)  30

Question 14

As frequency is varied in an RLC series circuit, resonance is reached when

Accepted Answer

A)  the voltages VR, VL and VC all become equal. 
B)  the voltages VL and VC become zero. 
C)  the voltage VR becomes equal to the source voltage. 
D)  None of the choices are correct. 
A)  the voltages VR, VL and VC all become equal. 
B)  the voltages VL and VC become zero. 
C)  the voltage VR becomes equal to the source voltage. 
D)  None of the choices are correct.

Question 15

A series RLC ac circuit has a capacitive reactance of 55 Ω, an inductive reactance of 25 Ω, and a resistance of 40 Ω. What is the phase constant of this circuit?

Accepted Answer

A)  37° 
B)  −37° 
C)  53° 
D)  −53° 
E)  66° 
A)  37° 
B)  −37° 
C)  53° 
D)  −53° 
E)  66°

Question 16

A 150 W light bulb is designed for an ac voltage of 120 V rms. What is the resistance of the bulb?

Accepted Answer

A)  150 Ω 
B)  144 Ω 
C)  96 Ω 
D)  68 Ω 
E)  48 Ω 
A)  150 Ω 
B)  144 Ω 
C)  96 Ω 
D)  68 Ω 
E)  48 Ω

Question 17

A 2.2 k Ω resistor and a 2.0 μF capacitor are connected in series in an ac circuit. The rms voltages across each are equal. What is the frequency?

Accepted Answer

A)  23 Hz 
B)  15 Hz 
C)  72 Hz 
D)  36 Hz 
E)  There is insufficient information to solve. 
A)  23 Hz 
B)  15 Hz 
C)  72 Hz 
D)  36 Hz 
E)  There is insufficient information to solve.

Question 18

An ac circuit consists of a 220 mH inductor in series with a 25 pF capacitor and an ac source with an rms voltage of 12 V. At what frequency will the rms voltage across the capacitor be equal to that across the inductor?

Accepted Answer

A)  94 kHz 
B)  15 kHz 
C)  68 kHz 
D)  426 kHz 
A)  94 kHz 
B)  15 kHz 
C)  68 kHz 
D)  426 kHz

Question 19

What is the period for a frequency of 60 Hz?

Accepted Answer

A)  60 s 
B)  (1/60) s 
C)  120 s 
D)  (1/120) s 
E)  (1/377) s 
A)  60 s 
B)  (1/60) s 
C)  120 s 
D)  (1/120) s 
E)  (1/377) s

Question 20

A bulb is designed for 100 W at 130 V rms. What is the power dissipated by this bulb if it is used in a 120 V rms circuit?

Accepted Answer

A)  169 W 
B)  130 W 
C)  100 W 
D)  85 W 
E)  it will blow out 
A)  169 W 
B)  130 W 
C)  100 W 
D)  85 W 
E)  it will blow out

Exam 21: Alternating Current

The average power dissipated in an RLC series circuit at resonance is dependent upon

An RLC series circuit has a 400 Ω resistance, a 2.5 mH inductor, and a capacitor. If the resonant frequency is 30 kHz, what is the capacitive reactance at resonance?

A series RLC circuit has resistance 200 Ω, inductance 0.200 H, and capacitance 0.500 μF. If the circuit is at resonance with a 120 V rms source, what is the average power dissipated?

The inductive reactance of an RLC circuit is 36 Ω. If the frequency is doubled, what is the new inductive reactance?

As the ac frequency in an RLC circuit is increased to very high values, which of the contributions to the impedance dominates?

An ac circuit consists of a 220 mH inductor in series with a 75 kΩ resistor and a sinusoidal source with an rms voltage of 12 V. At what frequency will the rms voltage across the resistor be equal to that across the inductor?

In an RLC ac circuit the current in the inductor and the current in the resistor are

What is the peak (maximum) power dissipated by a 150 W light bulb attached to a 120 V rms ac line?

An ac circuit consists of a 220 mH inductor in series with a 25 pF capacitor and a sinusoidal ac generator with an rms voltage of 12 V. If the frequency of the generator is 55 kHz, what will the rms voltage across the capacitor be?

An RLC series circuit has a 22 Ω resistor, a 3.0 H inductor, and a capacitor. What capacitance would result in resonance at 60 Hz?

For an ideal inductor in an ac circuit, how much energy is stored in the inductor at the instant when the current is zero?

What is the capacitance of a capacitor with a reactance of 20.0 Ω at a frequency of 60.0 Hz?

A lightbulb is connected to a 120 V (rms), 60 Hz source. How many times per second does the current reverse directions?

As frequency is varied in an RLC series circuit, resonance is reached when

A series RLC ac circuit has a capacitive reactance of 55 Ω, an inductive reactance of 25 Ω, and a resistance of 40 Ω. What is the phase constant of this circuit?

A 150 W light bulb is designed for an ac voltage of 120 V rms. What is the resistance of the bulb?

A 2.2 k Ω resistor and a 2.0 μF capacitor are connected in series in an ac circuit. The rms voltages across each are equal. What is the frequency?

An ac circuit consists of a 220 mH inductor in series with a 25 pF capacitor and an ac source with an rms voltage of 12 V. At what frequency will the rms voltage across the capacitor be equal to that across the inductor?

What is the period for a frequency of 60 Hz?

A bulb is designed for 100 W at 130 V rms. What is the power dissipated by this bulb if it is used in a 120 V rms circuit?

Introduction

Motion Along a Line

Motion in a Plane

Force and Newtons Laws of Motion

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Sound

Temperature and the Ideal Gas

Heat

Thermodynamics

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Magnetic Forces and Fields

Electromagnetic Induction

Electromagnetic Waves

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters