Question 1

If you triple the rms voltage in an ac circuit, what happens to the maximum voltage?

Accepted Answer

A)  It increases by a factor of   . 
B)  It decreases by a factor of   . 
C)  It decreases by a factor of 3. 
D)  It increases by a factor of 3. 
E)  It increases by a factor of 9. 
A)  It increases by a factor of   . 
B)  It decreases by a factor of   . 
C)  It decreases by a factor of 3. 
D)  It increases by a factor of 3. 
E)  It increases by a factor of 9.

Question 2

An ac signal of a certain frequency is applied to a capacitor. The current leads the voltage by 90°.

Accepted Answer

A) True 
 B)False

Question 3

A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. When this system reaches its steady-state, the voltage across the resistor is

Accepted Answer

A)  greater than the battery's terminal voltage. 
B)  equal to the battery's terminal voltage. 
C)  less than the battery's terminal voltage, but greater than zero. 
D)  zero. 
A)  greater than the battery's terminal voltage. 
B)  equal to the battery's terminal voltage. 
C)  less than the battery's terminal voltage, but greater than zero. 
D)  zero.

Question 4

A total impedance of an RC circuit with a capacitance of 40.0 μF is 800 Ω. If the frequency of the applied ac voltage is 18.0 Hz, what is the resistance of the circuit?

Accepted Answer

A)  569 Ω 
B)  669 Ω 
C)  769 Ω 
D)  869 Ω 
E)  800 Ω 
A)  569 Ω 
B)  669 Ω 
C)  769 Ω 
D)  869 Ω 
E)  800 Ω

Question 5

An ac signal at a certain frequency is applied across a 40-mH inductor and a 100-Ω resistor. If the power factor of this circuit is 0.40, what is the value of the frequency?

Accepted Answer

A)  160 Hz 
B)  200 Hz 
C)  410 Hz 
D)  600 Hz 
E)  910 Hz 
A)  160 Hz 
B)  200 Hz 
C)  410 Hz 
D)  600 Hz 
E)  910 Hz

Question 6

A series RLC circuit connected across an ac voltage source will have a positive value of the phase angle at high frequencies.

Accepted Answer

A) True 
 B)False

Question 7

Consider a series circuit in which the capacitive reactance equals the inductive reactance. What is the phase angle between current and voltage?

Accepted Answer

A)  +180.° 
B)  +90.° 
C)  -180.° 
D)  -90.° 
E)  0.° 
A)  +180.° 
B)  +90.° 
C)  -180.° 
D)  -90.° 
E)  0.°

Question 8

Resonance in a series RLC circuit occurs when

Accepted Answer

A)  XL is greater than XC. 
B)  XC is greater than XL. 
C)  (XL - X
C)  is equal to R2. 
D)  (XL - X
C) 2 is equal to R2. 
E)  XC equals XL. 
A)  XL is greater than XC. 
B)  XC is greater than XL. 
C)  (XL - X
C)  is equal to R2. 
D)  (XL - X
C) 2 is equal to R2. 
E)  XC equals XL.

Question 9

A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the resistor is

Accepted Answer

A)  greater than the battery's terminal voltage. 
B)  equal to the battery's terminal voltage. 
C)  less than the battery's terminal voltage, but greater than zero. 
D)  zero. 
A)  greater than the battery's terminal voltage. 
B)  equal to the battery's terminal voltage. 
C)  less than the battery's terminal voltage, but greater than zero. 
D)  zero.

Question 10

A 200-Ω resistor, a 40.0-mH inductor and a 2.00-μF capacitor are connected in series with a 120-V rms source at 1000 Hz. What is the impedance of this circuit?

Accepted Answer

A)  164 Ω 
B)  120 Ω 
C)  264 Ω 
D)  200 Ω 
E)  364 Ω 
A)  164 Ω 
B)  120 Ω 
C)  264 Ω 
D)  200 Ω 
E)  364 Ω

Question 11

The phase angle of an RLC 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 Ω 
A)  100 Ω 
B)  119 Ω 
C)  156 Ω 
D)  200 Ω 
E)  265 Ω

Question 12

A series RLC circuit has a 100-Ω resistor, 2.00-mH inductor and a 4.00-μF capacitor connected across a 120-V rms ac source at (1000/π) Hz. What is the power dissipated by the circuit?

Accepted Answer

A)  184 W 
B)  18.6 W 
C)  58.4 W 
D)  91.8 W 
E)  180 W 
A)  184 W 
B)  18.6 W 
C)  58.4 W 
D)  91.8 W 
E)  180 W

Question 13

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

Accepted Answer

A)  120 mV 
B)  87.1 mV 
C)  302 mV 
D)  96.1 mV 
E)  200 mV 
A)  120 mV 
B)  87.1 mV 
C)  302 mV 
D)  96.1 mV 
E)  200 mV

Question 14

In a RLC 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. 
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.

Question 15

A 120-V rms voltage at 2000 Hz is applied to a 6.0-mH inductor, a 2.0-μF capacitor and a 200-Ω resistor. What is the rms value of the current in this circuit?

Accepted Answer

A)  1.5 A 
B)  0.48 A 
C)  2.5 A 
D)  3.5 A 
E)  0.59 A 
A)  1.5 A 
B)  0.48 A 
C)  2.5 A 
D)  3.5 A 
E)  0.59 A

Question 16

In a RLC circuit, the values of the inductance and capacitance are both doubled. In comparison with the resonance frequency of the original circuit, the new resonant frequency will be

Accepted Answer

A)  the same as before. 
B)  reduced to one-half the original value. 
C)  reduced to one-quarter the original value. 
D)  increased by a factor of two. 
E)  increased by a factor of four. 
A)  the same as before. 
B)  reduced to one-half the original value. 
C)  reduced to one-quarter the original value. 
D)  increased by a factor of two. 
E)  increased by a factor of four.

Question 17

A capacitor with a capacitive reactance of 40.0 Ω is connected in series with a 100-Ω resistor across an ac source of frequency 60.0 Hz. What is the phase angle?

Accepted Answer

A)  +68.2° 
B)  -68.2° 
C)  -21.8° 
D)  +21.8° 
E)  90.0° 
A)  +68.2° 
B)  -68.2° 
C)  -21.8° 
D)  +21.8° 
E)  90.0°

Question 18

A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the capacitor is

Accepted Answer

A)  greater than the battery's terminal voltage. 
B)  equal to the battery's terminal voltage. 
C)  less than the battery's terminal voltage, but greater than zero. 
D)  zero. 
A)  greater than the battery's terminal voltage. 
B)  equal to the battery's terminal voltage. 
C)  less than the battery's terminal voltage, but greater than zero. 
D)  zero.

Question 19

The capacitive reactance increases with the capacitance.

Accepted Answer

A) True 
 B)False

Question 20

The capacitive reactance is directly proportional to the frequency of the applied ac signal.

Accepted Answer

A) True 
 B)False

Exam 24: Alternating-Current Circuits

If you triple the rms voltage in an ac circuit, what happens to the maximum voltage?

An ac signal of a certain frequency is applied to a capacitor. The current leads the voltage by 90°.

A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. When this system reaches its steady-state, the voltage across the resistor is

A total impedance of an RC circuit with a capacitance of 40.0 μF is 800 Ω. If the frequency of the applied ac voltage is 18.0 Hz, what is the resistance of the circuit?

An ac signal at a certain frequency is applied across a 40-mH inductor and a 100-Ω resistor. If the power factor of this circuit is 0.40, what is the value of the frequency?

A series RLC circuit connected across an ac voltage source will have a positive value of the phase angle at high frequencies.

Consider a series circuit in which the capacitive reactance equals the inductive reactance. What is the phase angle between current and voltage?

Resonance in a series RLC circuit occurs when

A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the resistor is

A 200-Ω resistor, a 40.0-mH inductor and a 2.00-μF capacitor are connected in series with a 120-V rms source at 1000 Hz. What is the impedance of this circuit?

The phase angle of an RLC 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?

A series RLC circuit has a 100-Ω resistor, 2.00-mH inductor and a 4.00-μF capacitor connected across a 120-V rms ac source at (1000/π) Hz. What is the power dissipated by the circuit?

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

In a RLC 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?

A 120-V rms voltage at 2000 Hz is applied to a 6.0-mH inductor, a 2.0-μF capacitor and a 200-Ω resistor. What is the rms value of the current in this circuit?

In a RLC circuit, the values of the inductance and capacitance are both doubled. In comparison with the resonance frequency of the original circuit, the new resonant frequency will be

A capacitor with a capacitive reactance of 40.0 Ω is connected in series with a 100-Ω resistor across an ac source of frequency 60.0 Hz. What is the phase angle?

A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the capacitor is

The capacitive reactance increases with the capacitance.

The capacitive reactance is directly proportional to the frequency of the applied ac signal.

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric Potential Energy

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

Filters