Question 1

A series LR circuit dissipates an average power of 60 W. The circuit is powered by a 120 V rms 60 Hz supply. If the current is 2.0 A rms, what is the phase constant?

Accepted Answer

A)  14° 
B)  25° 
C)  60° 
D)  70° 
E)  76° 
A)  14° 
B)  25° 
C)  60° 
D)  70° 
E)  76°

Question 2

The average value of sin2ωt for a complete cycle is

Accepted Answer

A)  1. 
B)  0. 
C)  0.707. 
D)  0.500. 
E)  0.250. 
A)  1. 
B)  0. 
C)  0.707. 
D)  0.500. 
E)  0.250.

Question 3

A 150 W light bulb is operating on a 120 V rms ac line. What is the rms current in the bulb?

Accepted Answer

A)  2.50 A 
B)  1.67 A 
C)  1.50 A 
D)  1.25 A 
E)  0.883 A 
A)  2.50 A 
B)  1.67 A 
C)  1.50 A 
D)  1.25 A 
E)  0.883 A

Question 4

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 inductor be?

Accepted Answer

A)  5.4 V 
B)  23 V 
C)  6.6 V 
D)  0.20 V 
A)  5.4 V 
B)  23 V 
C)  6.6 V 
D)  0.20 V

Question 5

In an ac circuit, the current in a capacitor

Accepted Answer

A)  leads the voltage by 90°. 
B)  lags the voltage by 90°. 
C)  is in phase with the voltage. 
D)  leads the voltage by π radians. 
E)  lags the voltage by π radians. 
A)  leads the voltage by 90°. 
B)  lags the voltage by 90°. 
C)  is in phase with the voltage. 
D)  leads the voltage by π radians. 
E)  lags the voltage by π radians.

Question 6

An ac circuit has a 20 μF capacitor, an 80 mH inductor, and a 60 Ω resistor in series. If the voltage source has an angular frequency of 1000 rad/s, what is the phase constant for the circuit?

Accepted Answer

A)  27° 
B)  53° 
C)  45° 
D)  63° 
E)  88° 
A)  27° 
B)  53° 
C)  45° 
D)  63° 
E)  88°

Question 7

An ac circuit consists of a 220 mH inductor in series with a 75 kΩ resistor and a 12 V rms sinusoidal ac generator. If the frequency of the generator is 25 kHz, what is the rms voltage across the inductor?

Accepted Answer

A)  7.0 V 
B)  2.6 V 
C)  9.4 V 
D)  5.0 V 
A)  7.0 V 
B)  2.6 V 
C)  9.4 V 
D)  5.0 V

Question 8

An RLC series circuit has a 400 Ω resistance, a 2.5 mH inductor, and a capacitor. If the resonant frequency is 30.0 kHz, and the circuit is attached to a 20 mV rms power supply, what is the rms voltage across the inductor at resonance?

Accepted Answer

A)  20 mV 
B)  24 mV 
C)  16 mV 
D)  48 mV 
E)  0.00 
A)  20 mV 
B)  24 mV 
C)  16 mV 
D)  48 mV 
E)  0.00

Question 9

An RLC series circuit has a 200 Ωresistance, a 3.0 mH inductor, and a 100 μF capacitor. What is the resonant frequency for this circuit?

Accepted Answer

A)  1.8 kHz 
B)  1.8 MHz 
C)  290 Hz 
D)  290 kHz 
E)  11 kHz 
A)  1.8 kHz 
B)  1.8 MHz 
C)  290 Hz 
D)  290 kHz 
E)  11 kHz

Question 10

A 25 nH inductor is connected to a 12 V rms ac source. At what frequency must the source drive the circuit if the rms current is to be 2.0 mA?

Accepted Answer

A)  38 GHz 
B)  240 GHz 
C)  0.15 MHz 
D)  0.96 MHz 
A)  38 GHz 
B)  240 GHz 
C)  0.15 MHz 
D)  0.96 MHz

Question 11

A series LR circuit dissipates an average power of 60 W. The circuit is powered by a 120 V rms 60 Hz supply. If the current is 2.0 A rms, what is the circuit resistance?

Accepted Answer

A)  50 Ω 
B)  60 Ω 
C)  15 Ω 
D)  10 Ω 
E)  24 Ω 
A)  50 Ω 
B)  60 Ω 
C)  15 Ω 
D)  10 Ω 
E)  24 Ω

Question 12

Two 100 W bulbs differ in that one is designed for the North American 120 V rms electric supply, while the other is designed for the European 220 V rms. Which bulb has the greater resistance, and what is that resistance?

Accepted Answer

A)  North American, 288 Ω 
B)  North American, 144 Ω 
C)  European, 484 Ω 
D)  European, 242 Ω 
E)  they are the same, 265 Ω 
A)  North American, 288 Ω 
B)  North American, 144 Ω 
C)  European, 484 Ω 
D)  European, 242 Ω 
E)  they are the same, 265 Ω

Question 13

In a series RLC circuit the rms voltage across the resistor is 80.0 V, across the capacitor is 120 V, and across the inductor is 60.0 V. What is the rms voltage applied to this circuit?

Accepted Answer

A)  60.0 V 
B)  80.0 V 
C)  100 V 
D)  120 V 
E)  140 V 
A)  60.0 V 
B)  80.0 V 
C)  100 V 
D)  120 V 
E)  140 V

Exam 21: Alternating Current

A series LR circuit dissipates an average power of 60 W. The circuit is powered by a 120 V rms 60 Hz supply. If the current is 2.0 A rms, what is the phase constant?

The average value of sin2ωt for a complete cycle is

A 150 W light bulb is operating on a 120 V rms ac line. What is the rms current in the bulb?

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 inductor be?

In an ac circuit, the current in a capacitor

An ac circuit has a 20 μF capacitor, an 80 mH inductor, and a 60 Ω resistor in series. If the voltage source has an angular frequency of 1000 rad/s, what is the phase constant for the circuit?

An ac circuit consists of a 220 mH inductor in series with a 75 kΩ resistor and a 12 V rms sinusoidal ac generator. If the frequency of the generator is 25 kHz, what is the rms voltage across the inductor?

An RLC series circuit has a 400 Ω resistance, a 2.5 mH inductor, and a capacitor. If the resonant frequency is 30.0 kHz, and the circuit is attached to a 20 mV rms power supply, what is the rms voltage across the inductor at resonance?

An RLC series circuit has a 200 Ωresistance, a 3.0 mH inductor, and a 100 μF capacitor. What is the resonant frequency for this circuit?

A 25 nH inductor is connected to a 12 V rms ac source. At what frequency must the source drive the circuit if the rms current is to be 2.0 mA?

A series LR circuit dissipates an average power of 60 W. The circuit is powered by a 120 V rms 60 Hz supply. If the current is 2.0 A rms, what is the circuit resistance?

Two 100 W bulbs differ in that one is designed for the North American 120 V rms electric supply, while the other is designed for the European 220 V rms. Which bulb has the greater resistance, and what is that resistance?

In a series RLC circuit the rms voltage across the resistor is 80.0 V, across the capacitor is 120 V, and across the inductor is 60.0 V. What is the rms voltage applied to this 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

The average value of sin²ωt for a complete cycle is