Question 1

If the ac peak current through a 100 ohm resistor is 1.7 A, the average power dissipated by the resistance is

Accepted Answer

A)  85 W.
B)  170 W.
C)  289 W.
D)  220 W.
E)  145 W.F) B) and D)
G) A) and E)

Question 2

If the ac peak current through a 100 ohm resistor is 1.7 A, the peak voltage across this resistor is

Accepted Answer

A)  289 V.
B)  110 V.
C)  170 V.
D)  210 V.
E)  120 V.F) A) and B)
G) None of the above

Question 3

A series LR circuit consists of a 2.0-H inductor with negligible internal resistance, a 100-ohm resistor, a switch, and a 9.0-V power source. After the switch is closed, what is the maximum power delivered by the power supply?

Accepted Answer

A)  0.40 W
B)  81 W
C)  0.090 W
D)  8.1 W
E)  0.81 WF) A) and B)
G) A) and C)

Question 4

What is the average power dissipated by a resistor of resistance R = 25 Ω in an LRC circuit for which the power factor is equal to 0.25 and the maximum voltage of the AC source is 8 V?

Accepted Answer

A)  0.04 W
B)  0.32 W
C)  0.16 W
D)  0.62 W
E)  0.08 WF) B) and D)
G) None of the above

Question 5

An LR circuit includes a resistor of resistance R, an inductor of inductance L and a battery of emf E = 10 V. At time t = 0 the current in the circuit is I = 0. At time t = 6.1 ms the current is I = 0.66 A. What are the values of L and R?

Accepted Answer

A)  not enough information given
B)  L = 15 mH, R = 20 Ω
C)  L = 10 mH, R = 100 Ω
D)  L = 50 mH, R = 150 Ω
E)  L = 2 mH, R = 10 ΩF) A) and D)
G) B) and E)

Question 6

The energy stored in the earth's magnetic field with a strength of 0.5 × 10-4 T in a room 3.0 m by 4.0 m by 2.4 m is

Accepted Answer

A)  570 mJ.
B)  29 mJ
C)  10 mJ.
D)  100 mJ.
E)  zero.F) B) and E)
G) D) and E)

Question 7

A 120-V rms voltage at 60.0 Hz is applied across an inductor, a capacitor, and a resistor in series. If the rms value of the current in this circuit is 0.600 A, what is the impedance of this circuit?

Accepted Answer

A)  200 Ω
B)  141 Ω
C)  20.4 Ω
D)  120 Ω
E)  100 ΩF) C) and D)
G) A) and B)

Question 8

In a LRC circuit, a second capacitor is connected in parallel with the capacitor previously in the circuit. What is the effect of this change on the impedance of the circuit?

Accepted Answer

A)  It increases.
B)  It decreases.
C)  It does not change.
D)  It increases for frequencies below resonance and decreases for frequencies above resonance.
E)  It decreases for frequencies below resonance and increases for frequencies above resonance.F) None of the above
G) A) and B)

Question 9

An electric circuit consists of a resistor connected across the terminals of an ac generator. How does the power dissipated in the resistor change as the frequency in the generator decreases?

Accepted Answer

A)  It decreases.
B)  It increases.
C)  It does not change.
D)  It increases or decreases depending on the sign of the phase angle.E) A) and B)
F) A) and D)

Question 10

An LRC circuit has R = 15 Ω, L = 25 mH, and C = 30 μF. The circuit is connected to a 120 V (rms) source with frequency 200 Hz.
(a) What is the average power dissipated by the circuit?
(b) What is the power factor for the circuit?

Accepted Answer

The answer of An LRC circuit has R = 15...

Question 11

Starting from zero, the electric current takes 2 seconds to reach half its maximum possible value in an RL circuit with a resistance R, an inductance L and a battery of emf E. How long will the current take to reach 75% its maximum value (measured from the moment when I = 0) ?

Accepted Answer

A)  8 s
B)  4 s
C)  10 s
D)  1 s
E)  2 sF) B) and D)
G) C) and D)

Question 12

What is the inductance of a solenoid 300 cm long, with 10.0 turns of wire and a cross-sectional area of 1.00 × 10-4 m2?

Accepted Answer

A)  4.19 nH
B)  4.19 pH
C)  4.19 μH
D)  4.19 mH
E)  4.19 fHF) B) and D)
G) None of the above

Question 13

A pure capacitor is connected to an ac power supply. In this circuit, the current

Accepted Answer

A)  leads the voltage by 90°.
B)  lags the voltage by 90°.
C)  lags the voltage by 180°.
D)  is in phase with the voltage.
E)  none of the given answersF) B) and D)
G) A) and E)

Question 14

A resistor is connected to an ac power supply. On this circuit, the current

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 45°.
E)  lags the voltage by 45°.F) A) and B)
G) B) and C)

Question 15

A series LRC circuit has a 100-Ω resistor, a 0.100-μF capacitor and a 2.00-mH inductor connected across a 120-V rms ac voltage source operating at (1000/π)  Hz. What is the resonant frequency of this circuit?

Accepted Answer

A)  70.7 kHz
B)  17.9 kHz
C)  22.5 kHz
D)  35.3 kHz
E)  11.3 kHzF) B) and C)
G) A) and E)

Question 16

In a LRC circuit, a second capacitor is connected in series with the capacitor previously in the circuit. What is the effect of this change on the impedance of the circuit?

Accepted Answer

A)  It increases.
B)  It decreases.
C)  It does not change.
D)  It increases for frequencies below resonance and decreases for frequencies above resonance.
E)  It decreases for frequencies below resonance and increases for frequencies above resonance.F) A) and D)
G) A) and C)

Question 17

Starting from zero, an electric current is established in a circuit made of a battery of emf E, a resistor of resistance R and an inductor of inductance L. The electric current eventually reaches its steady-state value. What would be the effect of using an inductor with a larger inductance in this circuit?

Accepted Answer

A)  The steady-state value of the current would be larger, but it would take the same amount of time to reach it.
B)  The steady-state value of the current would be the same, but it would take more time to reach it.
C)  The steady-state value of the current would be the same, but it would take the same amount of time to reach it.
D)  The steady-state value of the current would be larger, but it would take more time to reach it.
E)  The steady-state value of the current would be the same, but it would take less time to reach it.F) A) and C)
G) All of the above

Question 18

A wire of diameter d = 1 mm is wrapped around a cylindrical core of radius R = 5 cm and length l = 30 cm to build a solenoid. What is the energy stored in this solenoid when a current I = 0.2 A passes through it?

Accepted Answer

A)  1.2 × 10-4 J
B)  9.6 × 10-4 J
C)  4.8 × 10-4 J
D)  2.4 × 10-4 J
E)  0.6 × 10-4 JF) B) and D)
G) A) and B)

Question 19

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω and a capacitive reactance of 100 Ω is 40.0°. What is the value of the resistor in this circuit?

Accepted Answer

A)  100 Ω
B)  119 Ω
C)  156 Ω
D)  200 Ω
E)  265 ΩF) B) and D)
G) A) and C)

Question 20

What is the inductive reactance of a 20-mH inductor at a frequency of 60 Hz?

Accepted Answer

A)  7.5 Ω
B)  0.13 Ω
C)  1.2 Ω
D)  1.2 mΩ
E)  7.5 mΩF) None of the above
G) A) and E)

Exam 30: Inductance, Electromagnetic Oscillations, and Ac Circuits

An LR circuit includes a resistor of resistance R, an inductor of inductance L and a battery of emf E = 10 V. At time t = 0 the current in the circuit is I = 0. At time t = 6.1 ms the current is I = 0.66 A. What are the values of L and R?

Correct Answer
verified

An LRC circuit has R = 15 Ω, L = 25 mH, and C = 30 μF. The circuit is connected to a 120 V (rms) source with frequency 200 Hz. (a) What is the average power dissipated by the circuit? (b) What is the power factor for the circuit?

Correct Answer
verified

A resistor is connected to an ac power supply. On this circuit, the current

Correct Answer
verified

Starting from zero, the electric current takes 2 seconds to reach half its maximum possible value in an RL circuit with a resistance R, an inductance L and a battery of emf E. How long will the current take to reach 75% its maximum value (measured from the moment when I = 0) ?

Correct Answer
verified

An electric circuit consists of a resistor connected across the terminals of an ac generator. How does the power dissipated in the resistor change as the frequency in the generator decreases?

Correct Answer
verified

A series LRC circuit has a 100-Ω resistor, a 0.100-μF capacitor and a 2.00-mH inductor connected across a 120-V rms ac voltage source operating at (1000/π) Hz. What is the resonant frequency of this circuit?

Correct Answer
verified

In a LRC circuit, a second capacitor is connected in parallel with the capacitor previously in the circuit. What is the effect of this change on the impedance of the circuit?

Correct Answer
verified

A wire of diameter d = 1 mm is wrapped around a cylindrical core of radius R = 5 cm and length l = 30 cm to build a solenoid. What is the energy stored in this solenoid when a current I = 0.2 A passes through it?

Correct Answer
verified

What is the inductive reactance of a 20-mH inductor at a frequency of 60 Hz?

Correct Answer
verified

A series LR circuit consists of a 2.0-H inductor with negligible internal resistance, a 100-ohm resistor, a switch, and a 9.0-V power source. After the switch is closed, what is the maximum power delivered by the power supply?

Correct Answer
verified

If the ac peak current through a 100 ohm resistor is 1.7 A, the peak voltage across this resistor is

Correct Answer
verified

Correct Answer
verified

What is the inductance of a solenoid 300 cm long, with 10.0 turns of wire and a cross-sectional area of 1.00 × 10^-4 m²?

Correct Answer
verified

The energy stored in the earth's magnetic field with a strength of 0.5 × 10^-4 T in a room 3.0 m by 4.0 m by 2.4 m is

Correct Answer
verified

A 120-V rms voltage at 60.0 Hz is applied across an inductor, a capacitor, and a resistor in series. If the rms value of the current in this circuit is 0.600 A, what is the impedance of this circuit?

Correct Answer
verified

What is the average power dissipated by a resistor of resistance R = 25 Ω in an LRC circuit for which the power factor is equal to 0.25 and the maximum voltage of the AC source is 8 V?

Correct Answer
verified

If the ac peak current through a 100 ohm resistor is 1.7 A, the average power dissipated by the resistance is

Correct Answer
verified

In a LRC circuit, a second capacitor is connected in series with the capacitor previously in the circuit. What is the effect of this change on the impedance of the circuit?

Correct Answer
verified

A pure capacitor is connected to an ac power supply. In this circuit, the current

Correct Answer
verified

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω and a capacitive reactance of 100 Ω is 40.0°. What is the value of the resistor in this circuit?

Correct Answer
verified

Exam 30: Inductance, Electromagnetic Oscillations, and Ac Circuits

An LR circuit includes a resistor of resistance R, an inductor of inductance L and a battery of emf E = 10 V. At time t = 0 the current in the circuit is I = 0. At time t = 6.1 ms the current is I = 0.66 A. What are the values of L and R?

Correct AnswerverifiedShow Answer

An LRC circuit has R = 15 Ω, L = 25 mH, and C = 30 μF. The circuit is connected to a 120 V (rms) source with frequency 200 Hz. (a) What is the average power dissipated by the circuit? (b) What is the power factor for the circuit?

Correct AnswerverifiedShow Answer

A resistor is connected to an ac power supply. On this circuit, the current

Correct AnswerverifiedShow Answer

Starting from zero, the electric current takes 2 seconds to reach half its maximum possible value in an RL circuit with a resistance R, an inductance L and a battery of emf E. How long will the current take to reach 75% its maximum value (measured from the moment when I = 0) ?

Correct AnswerverifiedShow Answer

An electric circuit consists of a resistor connected across the terminals of an ac generator. How does the power dissipated in the resistor change as the frequency in the generator decreases?

Correct AnswerverifiedShow Answer

A series LRC circuit has a 100-Ω resistor, a 0.100-μF capacitor and a 2.00-mH inductor connected across a 120-V rms ac voltage source operating at (1000/π) Hz. What is the resonant frequency of this circuit?

Correct AnswerverifiedShow Answer

In a LRC circuit, a second capacitor is connected in parallel with the capacitor previously in the circuit. What is the effect of this change on the impedance of the circuit?

Correct AnswerverifiedShow Answer

A wire of diameter d = 1 mm is wrapped around a cylindrical core of radius R = 5 cm and length l = 30 cm to build a solenoid. What is the energy stored in this solenoid when a current I = 0.2 A passes through it?

Correct AnswerverifiedShow Answer

What is the inductive reactance of a 20-mH inductor at a frequency of 60 Hz?

Correct AnswerverifiedShow Answer

A series LR circuit consists of a 2.0-H inductor with negligible internal resistance, a 100-ohm resistor, a switch, and a 9.0-V power source. After the switch is closed, what is the maximum power delivered by the power supply?

Correct AnswerverifiedShow Answer

If the ac peak current through a 100 ohm resistor is 1.7 A, the peak voltage across this resistor is

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

What is the inductance of a solenoid 300 cm long, with 10.0 turns of wire and a cross-sectional area of 1.00 × 10-4 m2?

Correct AnswerverifiedShow Answer

The energy stored in the earth's magnetic field with a strength of 0.5 × 10-4 T in a room 3.0 m by 4.0 m by 2.4 m is

Correct AnswerverifiedShow Answer

A 120-V rms voltage at 60.0 Hz is applied across an inductor, a capacitor, and a resistor in series. If the rms value of the current in this circuit is 0.600 A, what is the impedance of this circuit?

Correct AnswerverifiedShow Answer

What is the average power dissipated by a resistor of resistance R = 25 Ω in an LRC circuit for which the power factor is equal to 0.25 and the maximum voltage of the AC source is 8 V?

Correct AnswerverifiedShow Answer

If the ac peak current through a 100 ohm resistor is 1.7 A, the average power dissipated by the resistance is

Correct AnswerverifiedShow Answer

In a LRC circuit, a second capacitor is connected in series with the capacitor previously in the circuit. What is the effect of this change on the impedance of the circuit?

Correct AnswerverifiedShow Answer

A pure capacitor is connected to an ac power supply. In this circuit, the current

Correct AnswerverifiedShow Answer

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω and a capacitive reactance of 100 Ω is 40.0°. What is the value of the resistor in this circuit?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What is the inductance of a solenoid 300 cm long, with 10.0 turns of wire and a cross-sectional area of 1.00 × 10^-4 m²?

Correct Answer
verified

The energy stored in the earth's magnetic field with a strength of 0.5 × 10^-4 T in a room 3.0 m by 4.0 m by 2.4 m is

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified