Question 1

The figure shows a uniform magnetic field that is normal to the plane of the conducting loop of resistance R.Note: the area of the non-circular portion of the circuit is negligible compared to that of the loop. 2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   A)    B)    C)    D)    E)   " class="answers-bank-image d-inline" rel="preload" >
-A circular loop of copper wire with an area of 2.0 m2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph. 2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   A)    B)    C)    D)    E)   " class="answers-bank-image d-inline" rel="preload" > Which one of the entries in the table below is incorrect? 2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   A)    B)    C)    D)    E)   " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
B)   2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
C)   2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
D)   2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
E)   2 lies in a plane perpendicular to a time-dependent magnetic field oriented as shown.The time-dependence of the field is shown in the graph.   Which one of the entries in the table below is incorrect?   
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >F) B) and D)
G) B) and C)

Question 2

The angular speed of a motor is 262 rad/s.The back emf generated by the motor is 89.4 V.Assuming all other factors remain the same, determine the back emf if the angular speed of the motor is reduced to 131 rad/s.

Accepted Answer

A)  32.3 V
B)  44.7 V
C)  52.5 V
D)  89.4 V
E)  152 VF) B) and E)
G) A) and E)

Question 3

22-3
A single conducting loop with an area of 2.0 m2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown. 2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown.   -A closed loop carries a current that increases with time.Which one of the quantities listed below relates the emf induced in the loop to the rate at which the current is increasing? A) resistance of the loop B) capacitance of the loop C) self-inductance of the loop D) power dissipated by the loop E) mutual inductance of the loop" class="answers-bank-image d-inline" rel="preload" >
-A closed loop carries a current that increases with time.Which one of the quantities listed below relates the emf induced in the loop to the rate at which the current is increasing?

Accepted Answer

A)  resistance of the loop
B)  capacitance of the loop
C)  self-inductance of the loop
D)  power dissipated by the loop
E)  mutual inductance of the loopF) B) and D)
G) A) and D)

Question 4

22-3
A single conducting loop with an area of 2.0 m2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown. 2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown.   -Determine the energy stored in a 7.09 × 10-7 H inductor that carries a 1.50-A current. A) 2.11 × 10-8 J B) 3.78 × 10-8 J C) 1.09 × 10-7 J D) 7.98 × 10-7 J E) 6.60 × 10-6 J" class="answers-bank-image d-inline" rel="preload" >
-Determine the energy stored in a 7.09 × 10-7 H inductor that carries a 1.50-A current.

Accepted Answer

A)  2.11 × 10-8 J
B)  3.78 × 10-8 J
C)  1.09 × 10-7 J
D)  7.98 × 10-7 J
E)  6.60 × 10-6 JF) B) and E)
G) B) and D)

Question 5

The figure shows a uniform magnetic field that is normal to the plane of the conducting loop of resistance R.Note: the area of the non-circular portion of the circuit is negligible compared to that of the loop. 
-Suppose that the radius of the loop is 0.500 m.At what rate must B change with time if the emf induced in the loop is 3  π\piπ volts?

Accepted Answer

A)  12.0 T/s
B)  18.8 T/s
C)  24.0 T/s
D)  37.7 T/s
E)  49.2 T/s F) All of the above
G) D) and E)

Question 6

Which one of the following statements concerning transformers is false?

Accepted Answer

A)  Their operation makes use of mutual induction.
B)  They are an application of Faraday's and Lenz's laws.
C)  A transformer can function with either an ac current or a steady dc current.
D)  A transformer that steps down the voltage, steps up the current.
E)  A transformer that steps up the voltage, steps down the current.F) A) and E)
G) A) and D)

Question 7

Two conducting loops carry equal currents I in the same direction as shown in the figure.If the current in the upper loop suddenly drops to zero, what will happen to the current in the lower loop according to Lenz's law?

Accepted Answer

A)  The current in the lower loop will decrease.
B)  The current in the lower loop will increase.
C)  The current in the lower loop will not change.
D)  The current in the lower loop will also drop to zero.
E)  The current in the lower loop will reverse its direction.F) All of the above
G) A) and B)

Question 8

A long, straight wire is in the same plane as a wooden, non-conducting loop.The wire carries an increasing current I in the direction shown in the figure.

Accepted Answer

A)  There will be no induced emf and no induced current.
B)  There will be a counterclockwise induced emf, but no induced current.
C)  There will be a clockwise induced emf, but no induced current.
D)  There will be a clockwise induced current in the loop.
E)  There will be a counterclockwise induced current in the loop.F) A) and B)
G) A) and E)

Question 9

A loop with a resistance of 4.0   Ω\OmegaΩ  is pushed to the left at a constant speed of 2.0 m/s by a 24 N force.At the instant shown in the figure, the loop is partially in and partially out of a uniform magnetic field.An induced current flows from left to right through the resistor.The length and width of the loop are 2.0 m and 1.0 m, respectively. 
-At what rate is energy dissipated by the resistor?

Accepted Answer

A)  130 W
B)  96 W
C)  32 W
D)  49 W
E)  8.0 W F) A) and B)
G) None of the above

Question 10

A loop with a resistance of 4.0   Ω\OmegaΩ  is pushed to the left at a constant speed of 2.0 m/s by a 24 N force.At the instant shown in the figure, the loop is partially in and partially out of a uniform magnetic field.An induced current flows from left to right through the resistor.The length and width of the loop are 2.0 m and 1.0 m, respectively. 
-Determine the magnitude of the uniform magnetic field.

Accepted Answer

A)  2.2 T
B)  3.5 T
C)  6.4 T
D)  7.0 T
E)  9.1 T F) A) and E)
G) B) and D)

Question 11

Two coils, 1 and 2, with iron cores are positioned as shown in the figure.Coil 1 is part of a circuit with a battery and a switch. 
-Assume that S has been closed for a long time.Which one of the following statements is true if S is suddenly opened?

Accepted Answer

A)  There is no induced current through R.
B)  There is no induced magnetic field in coil 2.
C)  There is an induced current in R that flows from right to left.
D)  There is an induced magnetic field in coil 2 that points toward C.
E)  There is an induced magnetic field in coil 2 that points toward B.F) A) and B)
G) C) and D)

Question 12

The figure shows a uniform, 3.0-T magnetic field that is normal to the plane of a conducting, circular loop with a resistance of 1.5   Ω\OmegaΩ  and a radius of 0.024 m.The magnetic field is directed out of the paper as shown.Note: The area of the non-circular portion of the wire is considered negligible compared to that of the circular loop. -2 W B) 3.6 × 10-2 W C) 3.8 × 10-3 W D) 2.7 × 10-4 W E) 4.9 × 10-4 W " class="answers-bank-image d-inline" rel="preload" >
-If the magnetic field is held constant at 3.0 T and the loop is pulled out of the region that contains the field in 0.2 s, at what rate is energy dissipated in R?

Accepted Answer

A)  1.8 × 10-2 W
B)  3.6 × 10-2 W
C)  3.8 × 10-3 W
D)  2.7 × 10-4 W
E)  4.9 × 10-4 W F) A) and B)
G) D) and E)

Question 13

Which of the following units are equivalent to those of motional emf?

Accepted Answer

A)  T . m/s
B)  V . m2/s
C)  J/s
D)  A .   Ω\OmegaΩ 
E)  T. m F) A) and B)
G) A) and C)

Question 14

A transformer has 450 turns in its primary coil and 30 turns in its secondary coil.Which one of the following statements concerning this transformer is true?

Accepted Answer

A)  This is a step-up transformer.
B)  The turns ratio is 15 for this transformer.
C)  The ratio of the voltages Vs / Vp is 15 for this transformer.
D)  The ratio of the currents Is / Ip is 0.067 for this transformer.
E)  The power delivered to the secondary must be the same as that delivered to the primary.F) All of the above
G) C) and D)

Question 15

The current in the secondary coil of a step-up transformer is 1.25 A when the current in the primary coil is 0.30 A.Determine the turns ratio, Ns/Np, of the transformer.

Accepted Answer

A)  5.6
B)  4.2
C)  0.24
D)  0.18
E)  0.12F) B) and C)
G) D) and E)

Question 16

22-4
A 0.100-m long solenoid has a radius of 0.050 m and 1.50 × 104 turns.The current in the solenoid changes at a rate of 6.0 A/s.A conducting loop of radius 0.0200 m is placed at the center of the solenoid with its axis the same as that of the solenoid as shown. 4 turns.The current in the solenoid changes at a rate of 6.0 A/s.A conducting loop of radius 0.0200 m is placed at the center of the solenoid with its axis the same as that of the solenoid as shown.   -Determine the self-induced emf in the solenoid due to the changing current. A) 60 V B) 98 V C) 130 V D) 180 V E) 250 V" class="answers-bank-image d-inline" rel="preload" >
-Determine the self-induced emf in the solenoid due to the changing current.

Accepted Answer

A)  60 V
B)  98 V
C)  130 V
D)  180 V
E)  250 VF) C) and E)
G) A) and B)

Question 17

A coil of wire with a resistance of 0.45   Ω\OmegaΩ  has a self-inductance of 0.083 H.If a 6.0-V battery is connected across the ends of the coil and the current in the circuit reaches an equilibrium value, what is the stored energy in the inductor?

Accepted Answer

A)  7.4 J
B)  4.6 J
C)  1.6 J
D)  5.1 J
E)  3.4 J F) D) and E)
G) C) and E)

Question 18

A conducting loop of wire is placed in a magnetic field that is normal to the plane of the loop.Which one of the following actions will not result in an induced current in the loop?

Accepted Answer

A)  Rotate the loop about an axis that is parallel to the field and passes through the center of the loop.
B)  Increase the strength of the magnetic field.
C)  Decrease the area of the loop.
D)  Decrease the strength of the magnetic field.
E)  Rotate the loop about an axis that is perpendicular to the field and passes through the center of the loop.F) A) and B)
G) A) and C)

Question 19

A sheet of copper is pulled at constant velocity v from a region that contains a uniform magnetic field.At the instant shown in the figure, the sheet is partially in and partially out of the field.The induced emf in the sheet leads to the eddy current shown.Which one of the following statements concerning the direction of the magnetic field is true?

Accepted Answer

A)  The magnetic field points to the right.
B)  The magnetic field points to the left.
C)  The magnetic field points into the paper.
D)  The magnetic field points out of the paper.
E)  The direction of the magnetic field cannot be determined from the information given.F) B) and D)
G) A) and D)

Question 20

A flexible, circular conducting loop of radius 0.15 m and resistance 4.0   Ω\OmegaΩ  lies in a uniform magnetic field of 0.25 T.The loop is pulled on opposite sides by equal forces and stretched until its enclosed area is essentially zero m2, as suggested in the drawings.It takes 0.30 s to close the loop. 2, as suggested in the drawings.It takes 0.30 s to close the loop.   -Which one of the following phrases best describes the direction of the induced magnetic field generated by the current induced in the loop while the loop is being stretched? A) clockwise B) counterclockwise C) into the page D) out of the page E) The induced field is zero. " class="answers-bank-image d-inline" rel="preload" >
-Which one of the following phrases best describes the direction of the induced magnetic field generated by the current induced in the loop while the loop is being stretched?

Accepted Answer

A)  clockwise
B)  counterclockwise
C)  into the page
D)  out of the page
E)  The induced field is zero. F) A) and B)
G) All of the above

Exam 22: Electromagnetic Induction

A conducting loop of wire is placed in a magnetic field that is normal to the plane of the loop.Which one of the following actions will not result in an induced current in the loop?

Correct Answer
verified

A coil of wire with a resistance of 0.45 $\Omega$ has a self-inductance of 0.083 H.If a 6.0-V battery is connected across the ends of the coil and the current in the circuit reaches an equilibrium value, what is the stored energy in the inductor?

Correct Answer
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The current in the secondary coil of a step-up transformer is 1.25 A when the current in the primary coil is 0.30 A.Determine the turns ratio, N_s/N_p, of the transformer.

Correct Answer
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Which one of the following statements concerning transformers is false?

Correct Answer
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The angular speed of a motor is 262 rad/s.The back emf generated by the motor is 89.4 V.Assuming all other factors remain the same, determine the back emf if the angular speed of the motor is reduced to 131 rad/s.

Correct Answer
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22-3 A single conducting loop with an area of 2.0 m² rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown. -Determine the energy stored in a 7.09 × 10^-⁷ H inductor that carries a 1.50-A current.

Correct Answer
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Correct Answer
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Two conducting loops carry equal currents I in the same direction as shown in the figure.If the current in the upper loop suddenly drops to zero, what will happen to the current in the lower loop according to Lenz's law?

Correct Answer
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Two coils, 1 and 2, with iron cores are positioned as shown in the figure.Coil 1 is part of a circuit with a battery and a switch. -Assume that S has been closed for a long time.Which one of the following statements is true if S is suddenly opened?

Correct Answer
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Which of the following units are equivalent to those of motional emf?

Correct Answer
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Correct Answer
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Correct Answer
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A long, straight wire is in the same plane as a wooden, non-conducting loop.The wire carries an increasing current I in the direction shown in the figure.

Correct Answer
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A transformer has 450 turns in its primary coil and 30 turns in its secondary coil.Which one of the following statements concerning this transformer is true?

Correct Answer
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Correct Answer
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Exam 22: Electromagnetic Induction

A conducting loop of wire is placed in a magnetic field that is normal to the plane of the loop.Which one of the following actions will not result in an induced current in the loop?

Correct AnswerverifiedShow Answer

A coil of wire with a resistance of 0.45 Ω\OmegaΩ has a self-inductance of 0.083 H.If a 6.0-V battery is connected across the ends of the coil and the current in the circuit reaches an equilibrium value, what is the stored energy in the inductor?

Correct AnswerverifiedShow Answer

The current in the secondary coil of a step-up transformer is 1.25 A when the current in the primary coil is 0.30 A.Determine the turns ratio, Ns/Np, of the transformer.

Correct AnswerverifiedShow Answer

Which one of the following statements concerning transformers is false?

Correct AnswerverifiedShow Answer

The angular speed of a motor is 262 rad/s.The back emf generated by the motor is 89.4 V.Assuming all other factors remain the same, determine the back emf if the angular speed of the motor is reduced to 131 rad/s.

Correct AnswerverifiedShow Answer

22-3 A single conducting loop with an area of 2.0 m2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown. -Determine the energy stored in a 7.09 × 10-7 H inductor that carries a 1.50-A current.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Two conducting loops carry equal currents I in the same direction as shown in the figure.If the current in the upper loop suddenly drops to zero, what will happen to the current in the lower loop according to Lenz's law?

Correct AnswerverifiedShow Answer

Two coils, 1 and 2, with iron cores are positioned as shown in the figure.Coil 1 is part of a circuit with a battery and a switch. -Assume that S has been closed for a long time.Which one of the following statements is true if S is suddenly opened?

Correct AnswerverifiedShow Answer

Which of the following units are equivalent to those of motional emf?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A long, straight wire is in the same plane as a wooden, non-conducting loop.The wire carries an increasing current I in the direction shown in the figure.

Correct AnswerverifiedShow Answer

A transformer has 450 turns in its primary coil and 30 turns in its secondary coil.Which one of the following statements concerning this transformer is true?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct Answer
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A coil of wire with a resistance of 0.45 $\Omega$ has a self-inductance of 0.083 H.If a 6.0-V battery is connected across the ends of the coil and the current in the circuit reaches an equilibrium value, what is the stored energy in the inductor?

Correct Answer
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The current in the secondary coil of a step-up transformer is 1.25 A when the current in the primary coil is 0.30 A.Determine the turns ratio, N_s/N_p, of the transformer.

Correct Answer
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Correct Answer
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Correct Answer
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22-3 A single conducting loop with an area of 2.0 m² rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown. -Determine the energy stored in a 7.09 × 10^-⁷ H inductor that carries a 1.50-A current.

Correct Answer
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Correct Answer
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