Question 1

An RLC series circuit is driven by a sinusoidal emf with angular frequency  d.If    d is increased without changing the amplitude of the emf, the current amplitude increases.If L is the inductance, C is the capacitance, and R is the resistance, this means that: A)     dL > 1/   dC  B)     dL dC  C)     dL = 1/   dC  D)     dL > R  E)     dL  d.If   d is increased without changing the amplitude of the emf, the current amplitude increases.If L is the inductance, C is the capacitance, and R is the resistance, this means that:

Accepted Answer

A)  "  dL > 1/  dC"
B)  "  dL dC"
C)  "  dL = 1/  dC"
D)  "  dL > R"
E)  "  dL < R"F) B) and C)
G) All of the above

Question 2

An RC series circuit is connected to an emf source having angular frequency  -1(1/   CR)  B) lags the source emf by tan-1(1/   CR)  C) leads the source emf by tan-1(   CR)  D) lags the source emf by tan-1(   CR)  E) leads the source emf by    /4" class="answers-bank-image d-inline" rel="preload" > .The current:

Accepted Answer

A)  leads the source emf by tan-1(1/  CR) 
B)  lags the source emf by tan-1(1/  CR) 
C)  leads the source emf by tan-1(  CR) 
D)  lags the source emf by tan-1(  CR) 
E)  leads the source emf by   /4F) C) and D)
G) B) and E)

Question 3

The angular frequency of a certain RLC series circuit is  ω\omegaω 0.A source of sinusoidal emf, with angular frequency  ω\omegaω , is inserted into the circuit and  ω\omegaω is varied while the amplitude of the source is held constant.For which of the following values of  ω\omegaω is the amplitude of the current oscillations the greatest?

Accepted Answer

A)  " ω\omegaω 0/5"
B)  " ω\omegaω 0/2"
C)  " ω\omegaω 0"
D)  "2 ω\omegaω 0"
E)  "None of them (they all produce the same current amplitude) " F) None of the above
G) A) and E)

Question 4

A capacitor in an LC oscillator has a maximum potential difference of 15 V and a maximum energy of 360  μ\muμ J.At a certain instant the energy in the capacitor is 40  μ\muμ J.At that instant what is the emf induced in the inductor?

Accepted Answer

A)  0 V
B)  5 V
C)  10 V
D)  15 V
E)  20 V F) A) and E)
G) D) and E) C

Question 5

For a power transmission line, the transmission should be at low current and high voltage because:

Accepted Answer

A)  this is the least dangerous to electrical workers
B)  this gives the least dose of electromagnetic radiation to the public
C)  this minimizes transmission losses
D)  low current and high voltage is easier to transform than high current and low voltage
E)  household appliances run at low current and high voltageF) B) and E)
G) D) and E)

Question 6

A 150-g block on the end of a spring with a spring constant of 35 N/m is pulled aside 25 cm and released from rest.In the electrical analog the initial charge on the capacitor is:

Accepted Answer

A)  0.15 C
B)  0.25 C
C)  8.8 C
D)  15 C
E)  35 CF) A) and E)
G) A) and D)

Question 7

In order to maximize the rate at which energy is supplied to a resistive load, the power factor of an RLC circuit should be as close as possible to:

Accepted Answer

A)  0
B)  0.5
C)  1
D)  infinity
E)  cannot tell without knowing R, L, C, and the driving frequencyF) All of the above
G) None of the above

Question 8

The rms value of a sinusoidal voltage is 0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   \mid V(t)  \mid .   A)    B)    C)    D)    E)    " class="answers-bank-image d-inline" rel="preload" > , where V0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   ∣\mid∣ V(t)  ∣\mid∣ . 0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   \mid V(t)  \mid .   A)    B)    C)    D)    E)    " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   \mid V(t)  \mid .   
A)     
B)     
C)     
D)     
E)     " class="answers-bank-image d-inline" rel="preload" >
B)   0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   \mid V(t)  \mid .   
A)     
B)     
C)     
D)     
E)     " class="answers-bank-image d-inline" rel="preload" >
C)   0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   \mid V(t)  \mid .   
A)     
B)     
C)     
D)     
E)     " class="answers-bank-image d-inline" rel="preload" >
D)   0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   \mid V(t)  \mid .   
A)     
B)     
C)     
D)     
E)     " class="answers-bank-image d-inline" rel="preload" >
E)   0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) =   \mid V(t)  \mid .   
A)     
B)     
C)     
D)     
E)     " class="answers-bank-image d-inline" rel="preload" > F) All of the above
G) A) and C)

Question 9

In an ideal 1:8 step-down transformer, the primary power is 10 kW and the secondary current is 25 A.The primary voltage is:

Accepted Answer

A)  25,600 V
B)  3200 V
C)  400 V
D)  50 V
E)  6.25 VF) A) and C)
G) B) and C)

Question 10

A 35- μ\muμ F capacitor is connected to an ac source of emf with a frequency of 400 Hz and a maximum emf of 20 V.The maximum current is:

Accepted Answer

A)  0 A
B)  0.28 A
C)  1.8 A
D)  230 A
E)  1400 A F) B) and E)
G) C) and D)

Question 11

In a series RLC circuit the rms value of the generator emf is 2/Z D) i2Z E) i2R " class="answers-bank-image d-inline" rel="preload" > and the rms value of the current is i.The current lags the emf by  ϕ\phiϕ  .The average power supplied by the generator is given by:

Accepted Answer

A)  (i 2/Z 
D)  i2Z 
E)  i2R " class="answers-bank-image d-inline" rel="preload" > /2) cos  ϕ\phiϕ  
B)  i 2/Z 
D)  i2Z 
E)  i2R " class="answers-bank-image d-inline" rel="preload" >
C)  i2/Z
D)  i2Z
E)  i2R F) A) and B)
G) All of the above

Question 12

In the circuit shown, switch S is first pushed up to charge the capacitor.When S is then pushed down, the current in the circuit will oscillate at a frequency of: 0" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  0.010 Hz
B)  12.5 Hz
C)  320 Hz
D)  2000 Hz
E)  depends on V0F) D) and E)
G) A) and B)

Question 13

In a sinusoidally driven series RLC circuit, the inductive resistance is XL = 200 Ω\OmegaΩ , the capacitive reactance is XC = 100  Ω\OmegaΩ , and the resistance is R = 50  Ω\OmegaΩ .The current and applied emf would be in phase if:

Accepted Answer

A)  the resistance is increased to 100  Ω\OmegaΩ , with no other changes
B)  the resistance is increased to 200  Ω\OmegaΩ , with no other changes
C)  the inductance is reduced to zero, with no other changes
D)  the capacitance is doubled, with no other changes
E)  the capacitance is halved, with no other changes F) C) and D)
G) None of the above

Question 14

In a sinusoidally driven series RLC circuit the current lags the applied emf.The rate at which energy is dissipated in the resistor can be increased by:

Accepted Answer

A)  decreasing the capacitance and making no other changes
B)  increasing the capacitance and making no other changes
C)  increasing the inductance and making no other changes
D)  increasing the driving frequency and making no other changes
E)  decreasing the amplitude of the driving emf and making no other changesF) A) and B)
G) A) and C)

Question 15

Consider the mechanical system consisting of two springs and a block, as shown.Which one of the five electrical circuits (I, II, III, IV, V) is the analog of the mechanical system?

Accepted Answer

A)  I
B)  II
C)  III
D)  IV
E)  VF) A) and E)
G) B) and D) A

Question 16

An ac generator producing 10 V (rms) at 200 rad/s is connected in series with a 50-  Ω\OmegaΩ   resistor, a 400-mH inductor, and a 200-  Ω\OmegaΩ  F capacitor.The rms current is:

Accepted Answer

A)  0.125 A
B)  0.135 A
C)  0.18 A
D)  0.20 A
E)  0.40 A F) B) and C)
G) All of the above

Question 17

Iron, rather than copper, is used in the core of transformers because iron:

Accepted Answer

A)  can withstand a higher temperature
B)  has a greater resistivity
C)  has a very high permeability
D)  makes a good permanent magnet
E)  insulates the primary from the secondaryF) A) and E)
G) B) and D)

Question 18

An LC circuit has an oscillation frequency of 105 Hz.If C = 0.1 μ\muμ F, then L must be about:

Accepted Answer

A)  10 mH
B)  1 mH
C)  25  μ\muμ H
D)  2.5  μ\muμ H
E)  1 pH F) D) and E)
G) A) and C)

Question 19

A 150-g block on the end of a spring with a spring constant of 35 N/m is pulled aside 25 cm and released from rest.In the electrical analog the maximum charge on the capacitor is 0.25 C.The maximum current in the LC circuit is:

Accepted Answer

A)  0.025 A
B)  0.12 A
C)  3.8 A
D)  5.3 A
E)  40 AF) C) and E)
G) All of the above C

Question 20

In a purely capacitive circuit the current:

Accepted Answer

A)  leads the voltage by one-fourth of a cycle
B)  leads the voltage by one-half of a cycle
C)  lags the voltage by one-fourth of a cycle
D)  lags the voltage by one-half of a cycle
E)  is in phase with the potential difference across the platesF) B) and E)
G) A) and B)

Exam 31: Electromagnetic Oscillations and Alternating Current

Correct Answer
verified

An RC series circuit is connected to an emf source having angular frequency .The current:

Correct Answer
verified

Correct Answer
verified

A capacitor in an LC oscillator has a maximum potential difference of 15 V and a maximum energy of 360 $\mu$ J.At a certain instant the energy in the capacitor is 40 $\mu$ J.At that instant what is the emf induced in the inductor?

Correct Answer
verified
C

For a power transmission line, the transmission should be at low current and high voltage because:

Correct Answer
verified

A 150-g block on the end of a spring with a spring constant of 35 N/m is pulled aside 25 cm and released from rest.In the electrical analog the initial charge on the capacitor is:

Correct Answer
verified

In order to maximize the rate at which energy is supplied to a resistive load, the power factor of an RLC circuit should be as close as possible to:

Correct Answer
verified

Correct Answer
verified

In an ideal 1:8 step-down transformer, the primary power is 10 kW and the secondary current is 25 A.The primary voltage is:

Correct Answer
verified

A 35- $\mu$ F capacitor is connected to an ac source of emf with a frequency of 400 Hz and a maximum emf of 20 V.The maximum current is:

Correct Answer
verified

Correct Answer
verified

In the circuit shown, switch S is first pushed up to charge the capacitor.When S is then pushed down, the current in the circuit will oscillate at a frequency of:

Correct Answer
verified

In a sinusoidally driven series RLC circuit, the inductive resistance is X_L = 200 $\Omega$ , the capacitive reactance is X_C = 100 $\Omega$ , and the resistance is R = 50 $\Omega$ .The current and applied emf would be in phase if:

Correct Answer
verified

In a sinusoidally driven series RLC circuit the current lags the applied emf.The rate at which energy is dissipated in the resistor can be increased by:

Correct Answer
verified

Consider the mechanical system consisting of two springs and a block, as shown.Which one of the five electrical circuits (I, II, III, IV, V) is the analog of the mechanical system?

Correct Answer
verified
A

An ac generator producing 10 V (rms) at 200 rad/s is connected in series with a 50- $\Omega$ resistor, a 400-mH inductor, and a 200- $\Omega$ F capacitor.The rms current is:

Correct Answer
verified

Iron, rather than copper, is used in the core of transformers because iron:

Correct Answer
verified

An LC circuit has an oscillation frequency of 10⁵ Hz.If C = 0.1 $\mu$ F, then L must be about:

Correct Answer
verified

A 150-g block on the end of a spring with a spring constant of 35 N/m is pulled aside 25 cm and released from rest.In the electrical analog the maximum charge on the capacitor is 0.25 C.The maximum current in the LC circuit is:

Correct Answer
verified
C

In a purely capacitive circuit the current:

Correct Answer
verified

Exam 31: Electromagnetic Oscillations and Alternating Current

Correct AnswerverifiedShow Answer

An RC series circuit is connected to an emf source having angular frequency .The current:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A capacitor in an LC oscillator has a maximum potential difference of 15 V and a maximum energy of 360 μ\muμ J.At a certain instant the energy in the capacitor is 40 μ\muμ J.At that instant what is the emf induced in the inductor?

Correct AnswerverifiedC

For a power transmission line, the transmission should be at low current and high voltage because:

Correct AnswerverifiedShow Answer

A 150-g block on the end of a spring with a spring constant of 35 N/m is pulled aside 25 cm and released from rest.In the electrical analog the initial charge on the capacitor is:

Correct AnswerverifiedShow Answer

In order to maximize the rate at which energy is supplied to a resistive load, the power factor of an RLC circuit should be as close as possible to:

Correct AnswerverifiedShow Answer

The rms value of a sinusoidal voltage is , where V0 is the amplitude.What is the rms value of its fully rectified wave? Recall that Vrect(t) = ∣\mid∣ V(t) ∣\mid∣ .

Correct AnswerverifiedShow Answer

In an ideal 1:8 step-down transformer, the primary power is 10 kW and the secondary current is 25 A.The primary voltage is:

Correct AnswerverifiedShow Answer

A 35- μ\muμ F capacitor is connected to an ac source of emf with a frequency of 400 Hz and a maximum emf of 20 V.The maximum current is:

Correct AnswerverifiedShow Answer

In a series RLC circuit the rms value of the generator emf is and the rms value of the current is i.The current lags the emf by ϕ\phiϕ .The average power supplied by the generator is given by:

Correct AnswerverifiedShow Answer

In the circuit shown, switch S is first pushed up to charge the capacitor.When S is then pushed down, the current in the circuit will oscillate at a frequency of:

Correct AnswerverifiedShow Answer

In a sinusoidally driven series RLC circuit, the inductive resistance is XL = 200 Ω\OmegaΩ , the capacitive reactance is XC = 100 Ω\OmegaΩ , and the resistance is R = 50 Ω\OmegaΩ .The current and applied emf would be in phase if:

Correct AnswerverifiedShow Answer

In a sinusoidally driven series RLC circuit the current lags the applied emf.The rate at which energy is dissipated in the resistor can be increased by:

Correct AnswerverifiedShow Answer

Consider the mechanical system consisting of two springs and a block, as shown.Which one of the five electrical circuits (I, II, III, IV, V) is the analog of the mechanical system?

Correct AnswerverifiedA

An ac generator producing 10 V (rms) at 200 rad/s is connected in series with a 50- Ω\OmegaΩ resistor, a 400-mH inductor, and a 200- Ω\OmegaΩ F capacitor.The rms current is:

Correct AnswerverifiedShow Answer

Iron, rather than copper, is used in the core of transformers because iron:

Correct AnswerverifiedShow Answer

An LC circuit has an oscillation frequency of 105 Hz.If C = 0.1 μ\muμ F, then L must be about:

Correct AnswerverifiedShow Answer

A 150-g block on the end of a spring with a spring constant of 35 N/m is pulled aside 25 cm and released from rest.In the electrical analog the maximum charge on the capacitor is 0.25 C.The maximum current in the LC circuit is:

Correct AnswerverifiedC

In a purely capacitive circuit the current:

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

A capacitor in an LC oscillator has a maximum potential difference of 15 V and a maximum energy of 360 $\mu$ J.At a certain instant the energy in the capacitor is 40 $\mu$ J.At that instant what is the emf induced in the inductor?

Correct Answer
verified
C

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

A 35- $\mu$ F capacitor is connected to an ac source of emf with a frequency of 400 Hz and a maximum emf of 20 V.The maximum current is:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

In a sinusoidally driven series RLC circuit, the inductive resistance is X_L = 200 $\Omega$ , the capacitive reactance is X_C = 100 $\Omega$ , and the resistance is R = 50 $\Omega$ .The current and applied emf would be in phase if:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A

An ac generator producing 10 V (rms) at 200 rad/s is connected in series with a 50- $\Omega$ resistor, a 400-mH inductor, and a 200- $\Omega$ F capacitor.The rms current is:

Correct Answer
verified

Correct Answer
verified

An LC circuit has an oscillation frequency of 10⁵ Hz.If C = 0.1 $\mu$ F, then L must be about:

Correct Answer
verified

Correct Answer
verified
C

Correct Answer
verified