Question 1

Consider a 4500. ohm resistor in series with a 133. mH inductor. What capacitance should be added in series so that the impedance is a minimum at 500. KHz?

Accepted Answer

A)  0.627 pF 
B)  7.26 $\mu$F 
C)  0.762 pF 
D)  2.67 $\mu$F 
E)  0.267 pF 
A)  0.627 pF 
B)  7.26 $\mu$F 
C)  0.762 pF 
D)  2.67 $\mu$F 
E)  0.267 pF C

Question 2

If the inductance and the capacitance both double in an LRC series circuit, the resonant frequency of that circuit will

Accepted Answer

A)  decrease to one-half its original value. 
B)  increase to four times its original value. 
C)  increase to twice its original value. 
D)  decrease to one-fourth its original value. 
E)  decrease to one-eighth its original value. 
A)  decrease to one-half its original value. 
B)  increase to four times its original value. 
C)  increase to twice its original value. 
D)  decrease to one-fourth its original value. 
E)  decrease to one-eighth its original value. A

Question 3

A resistance of 55.  , a capacitor of capacitive reactance 30.  , and an inductor of inductive reactance 30.  are connected in series to a 110. V, 60. Hz power source. What current flows in this circuit?

Accepted Answer

A)  more than 4. A 
B)  2. A 
C)  more than 2. A but less than 4. A 
D)  4. A 
E)  less than 2. A 
A)  more than 4. A 
B)  2. A 
C)  more than 2. A but less than 4. A 
D)  4. A 
E)  less than 2. A B

Question 4

In an RLC circuit, the resistance is 10. ohms, the capacitive reactance is 30. ohms, and the inductive reactance is 50. ohms. What is the circuit impedance?

Accepted Answer

A)  63.   
B)  22.   
C)  10.   
D)  81.   
E)  90.   
A)  63.   
B)  22.   
C)  10.   
D)  81.   
E)  90.

Question 5

The resonance frequency of an RLC circuit is the frequency at which the circuit dissipates minimum power.

Accepted Answer

A) True 
 B)False

Question 6

What is the reactance of a 1.0 mH inductor at 60 Hz?

Accepted Answer

The answer of What is the reactance of a 1.0...

Question 7

The current through a 50. $\Omega$ resistor is I = 0.80 sin (240. t) amperes. 
(a) At what frequency does the current vary? 
(b) How much power is dissipated in the resistor?

Accepted Answer

(a) 38. Hz

Question 8

A series RC circuit has resistance of 150 $\Omega$ and capacitance of 40. $\mu$F. It is driven by a 120. V, 60. Hz source.
(a) How much power is dissipated in the resistor?
(b) How much power is dissipated in the capacitor?

Accepted Answer

The answer of A series RC circuit has resistance of...

Question 9

An AC voltage source has an amplitude of 96. V and frequency 400. Hz. The voltage was zero at t = 0 and was increasing.
(a) What is the effective rms voltage?
(b) What is the instantaneous voltage at 1.00 ms?
(c) When will the voltage be 40. V?

Accepted Answer

(a) 68. V

Question 10

Which of the following doesn't have ohm units?

Accepted Answer

A)    L 
B)    C 
C)  (XcXc)/R 
D)  (XL - X
C)  
E)  R 
A)    L 
B)    C 
C)  (XcXc)/R 
D)  (XL - X
C)  
E)  R

Question 11

A series RL circuit is driven by a 120. V, 60. Hz source. The values of the resistance and inductance are R = 20.0 $\Omega$ and L = 160. mH. Determine:
(a) the current.
(b) the phase angle between the current and the applied voltage.

Accepted Answer

(a) I = 1.

Question 12

For an rms current of 5.0 amperes determine the maximum and peak-to-peak values.

Accepted Answer

7.1 Ampere

Question 13

Resonance in a series RLC circuit occurs when

Accepted Answer

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

Question 14

American power plants usually supply 120. volts AC:
(a) at what frequency?
(b) at what maximum voltage?

Accepted Answer

(a) 60. Hz

Question 15

What capacitance will have the same reactance as a 100. mH inductance in a 120. V, 60. Hz circuit?

Accepted Answer

The answer of What capacitance will have the same reactance...

Question 16

Compare the voltage waves from two different AC circuits, as shown in Figure 21-2.
  
 The absolute value of the phase difference is

Accepted Answer

A)  45°. 
B)  -90°. 
C)  90°. 
D)  zero. 
E)  180°. 
A)  45°. 
B)  -90°. 
C)  90°. 
D)  zero. 
E)  180°.

Question 17

If the frequency of the AC voltage across an inductor is doubled, the inductive reactance of that inductor

Accepted Answer

A)  increases to 4 times its original value. 
B)  decreases to one-half its original value. 
C)  decreases to one-fourth its original value. 
D)  increases to twice its original value. 
A)  increases to 4 times its original value. 
B)  decreases to one-half its original value. 
C)  decreases to one-fourth its original value. 
D)  increases to twice its original value.

Question 18

The polarity of the voltage in a circuit operating at 60 Hz reverses

Accepted Answer

A)  90 times per second. 
B)  10$\pi$ times per second. 
C)  30 times per second. 
D)  60 times per second. 
E)  120 times per second. 
A)  90 times per second. 
B)  10$\pi$ times per second. 
C)  30 times per second. 
D)  60 times per second. 
E)  120 times per second.

Question 19

The average power dissipated in an RLC circuit is I2 rms R where R is the Reactance.

Accepted Answer

A) True 
 B)False

Question 20

What is the average power if the current is Io sin($\omega$t) and the voltage is Vo sin($\omega$t) ?

Accepted Answer

(I<sub>o</

Exam 21: AC Circuits

Consider a 4500. ohm resistor in series with a 133. mH inductor. What capacitance should be added in series so that the impedance is a minimum at 500. KHz?

If the inductance and the capacitance both double in an LRC series circuit, the resonant frequency of that circuit will

A resistance of 55. , a capacitor of capacitive reactance 30. 11eea40e_f9c3_5706_97f4_d114cf755d2c_TB9720_11, and an inductor of inductive reactance 30.11eea40e_f9c3_5706_97f4_d114cf755d2c_TB9720_11 are connected in series to a 110. V, 60. Hz power source. What current flows in this circuit?

In an RLC circuit, the resistance is 10. ohms, the capacitive reactance is 30. ohms, and the inductive reactance is 50. ohms. What is the circuit impedance?

The resonance frequency of an RLC circuit is the frequency at which the circuit dissipates minimum power.

What is the reactance of a 1.0 mH inductor at 60 Hz?

The current through a 50. Ω\OmegaΩ resistor is I = 0.80 sin (240. t) amperes. (a) At what frequency does the current vary? (b) How much power is dissipated in the resistor?

A series RC circuit has resistance of 150 Ω\OmegaΩ and capacitance of 40. μ\muμ F. It is driven by a 120. V, 60. Hz source. (a) How much power is dissipated in the resistor? (b) How much power is dissipated in the capacitor?

An AC voltage source has an amplitude of 96. V and frequency 400. Hz. The voltage was zero at t = 0 and was increasing. (a) What is the effective rms voltage? (b) What is the instantaneous voltage at 1.00 ms? (c) When will the voltage be 40. V?

Which of the following doesn't have ohm units?

A series RL circuit is driven by a 120. V, 60. Hz source. The values of the resistance and inductance are R = 20.0 Ω\OmegaΩ and L = 160. mH. Determine: (a) the current. (b) the phase angle between the current and the applied voltage.

For an rms current of 5.0 amperes determine the maximum and peak-to-peak values.

Resonance in a series RLC circuit occurs when

American power plants usually supply 120. volts AC: (a) at what frequency? (b) at what maximum voltage?

What capacitance will have the same reactance as a 100. mH inductance in a 120. V, 60. Hz circuit?

Compare the voltage waves from two different AC circuits, as shown in Figure 21-2. The absolute value of the phase difference is

If the frequency of the AC voltage across an inductor is doubled, the inductive reactance of that inductor

The polarity of the voltage in a circuit operating at 60 Hz reverses

The average power dissipated in an RLC circuit is I2 rms R where R is the Reactance.

What is the average power if the current is Io sin( ω\omegaω t) and the voltage is Vo sin( ω\omegaω t) ?

Measurement and Problem Solving

Kinematics: Description of Motion

Motion in Two Dimensions

Force and Motion

Work and Energy

Linear Momentum and Collisions

Circular Motion and Gravitation

Rotational Motion and Equilibrium

Solids and Fluids

Temperature and Kinetic Theory

Heat

Thermodynamics

Vibrations and Waves

Sound

Electric Charge, Forces, and Fields

Electric Potential, Energy, and Capacitance

Electric Current and Resistance

Basic Electric Circuits

Magnetism

Electromagnetic Induction and Waves

Reflection and Refraction of Light

Mirrors and Lenses

Physical Optics: The Wave Nature of Light

Vision and Optical Instruments

Relativity

Quantum Physics

Quantum Mechanics and Atomic Physics

The Nucleus

Nuclear Reactions and Elementary Particles

Filters

The current through a 50. $\Omega$ resistor is I = 0.80 sin (240. t) amperes. (a) At what frequency does the current vary? (b) How much power is dissipated in the resistor?

A series RC circuit has resistance of 150 $\Omega$ and capacitance of 40. $\mu$ F. It is driven by a 120. V, 60. Hz source. (a) How much power is dissipated in the resistor? (b) How much power is dissipated in the capacitor?

A series RL circuit is driven by a 120. V, 60. Hz source. The values of the resistance and inductance are R = 20.0 $\Omega$ and L = 160. mH. Determine: (a) the current. (b) the phase angle between the current and the applied voltage.

The average power dissipated in an RLC circuit is I² rms R where R is the Reactance.

What is the average power if the current is I_o sin( $\omega$ t) and the voltage is V_o sin( $\omega$ t) ?