Question 1

A force field is induced in any region of space in which

Accepted Answer

A) an electric field changes with time. 
B) a magnetic field changes with time. 
C) both of these 
D) neither of these 
A) an electric field changes with time. 
B) a magnetic field changes with time. 
C) both of these 
D) neither of these

Question 2

When a change occurs in the magnetic field in a closed loop of wire

Accepted Answer

A) a voltage is induced in the wire. 
B) a current is created in the loop of wire. 
C) electromagnetic induction occurs. 
D) all of the above 
E) none of the above 
A) a voltage is induced in the wire. 
B) a current is created in the loop of wire. 
C) electromagnetic induction occurs. 
D) all of the above 
E) none of the above

Question 3

Disregarding the effects of friction, a cyclist will coast farther when a lamp powered by a wheel generator is

Accepted Answer

A) of low wattage. 
B) of high wattage. 
C) turned off. 
D) none of the above 
A) of low wattage. 
B) of high wattage. 
C) turned off. 
D) none of the above

Question 4

A generator armature is more difficult to rotate when supplying electric current due to

Accepted Answer

A) an induced magnetic field in the windings that resists change. 
B) increased resistance. 
C) energy leaking as heat. 
D) none of the above 
A) an induced magnetic field in the windings that resists change. 
B) increased resistance. 
C) energy leaking as heat. 
D) none of the above

Question 5

The current produced by a common generator is

Accepted Answer

A) dc. 
B) ac. 
C) neither of these 
A) dc. 
B) ac. 
C) neither of these

Question 6

The frequency of induced voltage in a wire coil depends on

Accepted Answer

A) the frequency of current producing it. 
B) how frequently a magnet dips in and out of the coil. 
C) the number of loops in the coil. 
A) the frequency of current producing it. 
B) how frequently a magnet dips in and out of the coil. 
C) the number of loops in the coil.

Question 7

Electromagnetic induction is employed in

Accepted Answer

A) electric power lines. 
B) triggering traffic lights. 
C) hybrid automobiles. 
D) mobile phones. 
E) all the above 
A) electric power lines. 
B) triggering traffic lights. 
C) hybrid automobiles. 
D) mobile phones. 
E) all the above

Question 8

A step-up transformer steps up voltage by ten times. Neglecting slight losses, if 100 W of power go into the primary coil, the power coming from the secondary coil is

Accepted Answer

A) 1 W. 
B) 10 W. 
C) 100 W. 
D) 1000 W. 
E) none of the above 
A) 1 W. 
B) 10 W. 
C) 100 W. 
D) 1000 W. 
E) none of the above

Question 9

Fred swings a sheet of copper in pendulum fashion between the poles of a strong magnet. The sheet slows in entering the magnetic field because it

Accepted Answer

A) induces swirling currents in the copper and accompanying magnetic fields that resist motion. 
B) experiences both air and magnetic friction. 
C) is repelled by free electrons in the copper. 
D) none of the above 
A) induces swirling currents in the copper and accompanying magnetic fields that resist motion. 
B) experiences both air and magnetic friction. 
C) is repelled by free electrons in the copper. 
D) none of the above

Question 10

When voltage is induced in a coil of wire, current is

Accepted Answer

A) also induced. 
B) not induced. 
C) cancelled. 
A) also induced. 
B) not induced. 
C) cancelled.

Question 11

A device that transforms electrical energy to mechanical energy is a

Accepted Answer

A) generator. 
B) motor. 
C) transformer. 
D) magnet. 
E) none of the above 
A) generator. 
B) motor. 
C) transformer. 
D) magnet. 
E) none of the above

Question 12

The rate at which energy is transferred is

Accepted Answer

A) power. 
B) electromagnetic induction. 
C) transformation. 
D) none of the above 
A) power. 
B) electromagnetic induction. 
C) transformation. 
D) none of the above

Question 13

Rapid change of a magnetic field induces

Accepted Answer

A) a magnetic field of greater magnitude. 
B) a magnetic field of the same magnitude. 
C) an electric field. 
A) a magnetic field of greater magnitude. 
B) a magnetic field of the same magnitude. 
C) an electric field.

Question 14

The principal advantage of ac power over dc power is that

Accepted Answer

A) more energy is dissipated during transmission. 
B) ac voltage oscillates while dc voltage does not. 
C) ac voltage can be transformed via conventional transformers. 
D) ac circuits multiply power more easily. 
E) ac circuits are safer. 
A) more energy is dissipated during transmission. 
B) ac voltage oscillates while dc voltage does not. 
C) ac voltage can be transformed via conventional transformers. 
D) ac circuits multiply power more easily. 
E) ac circuits are safer.

Question 15

An electric motor is very similar to

Accepted Answer

A) an electric generator. 
B) an automobile battery. 
C) a radio receiver. 
D) none of the above 
A) an electric generator. 
B) an automobile battery. 
C) a radio receiver. 
D) none of the above

Question 16

The strength of an induced electric or magnetic field depends on

Accepted Answer

A) strength of magnetic poles. 
B) alignment of magnetic domains. 
C) rate of change of the induced field. 
D) all of the above 
E) none of the above 
A) strength of magnetic poles. 
B) alignment of magnetic domains. 
C) rate of change of the induced field. 
D) all of the above 
E) none of the above

Question 17

If you thrust a magnet into a closed loop of wire, the loop will

Accepted Answer

A) rotate. 
B) have a current in it. 
C) both of these 
D) neither of these 
A) rotate. 
B) have a current in it. 
C) both of these 
D) neither of these

Question 18

Between the consumer and the power plant, most importantly, are

Accepted Answer

A) huge capacitors. 
B) generators. 
C) step-down transformers. 
D) all of the above 
E) none of the above 
A) huge capacitors. 
B) generators. 
C) step-down transformers. 
D) all of the above 
E) none of the above

Question 19

The primary of a transformer

Accepted Answer

A) has an iron core. 
B) may or may not have an iron core. 
C) has more turns of wire than the secondary. 
D) none of the above 
A) has an iron core. 
B) may or may not have an iron core. 
C) has more turns of wire than the secondary. 
D) none of the above

Question 20

Electromagnetic induction occurs in a coil when there is a change in

Accepted Answer

A) electric field intensity in the coil. 
B) magnetic field intensity in the coil. 
C) electromagnetic polarity. 
D) none of the above 
A) electric field intensity in the coil. 
B) magnetic field intensity in the coil. 
C) electromagnetic polarity. 
D) none of the above

Exam 25: Electromagnetic Induction

A force field is induced in any region of space in which

When a change occurs in the magnetic field in a closed loop of wire

Disregarding the effects of friction, a cyclist will coast farther when a lamp powered by a wheel generator is

A generator armature is more difficult to rotate when supplying electric current due to

The current produced by a common generator is

The frequency of induced voltage in a wire coil depends on

Electromagnetic induction is employed in

A step-up transformer steps up voltage by ten times. Neglecting slight losses, if 100 W of power go into the primary coil, the power coming from the secondary coil is

Fred swings a sheet of copper in pendulum fashion between the poles of a strong magnet. The sheet slows in entering the magnetic field because it

When voltage is induced in a coil of wire, current is

A device that transforms electrical energy to mechanical energy is a

The rate at which energy is transferred is

Rapid change of a magnetic field induces

The principal advantage of ac power over dc power is that

An electric motor is very similar to

The strength of an induced electric or magnetic field depends on

If you thrust a magnet into a closed loop of wire, the loop will

Between the consumer and the power plant, most importantly, are

The primary of a transformer

Electromagnetic induction occurs in a coil when there is a change in

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