Question 1

Disconnect a small-voltage battery from a coil of many loops of wire and a large voltage is produced by

Accepted Answer

A) the sudden collapse in the magnetic field. 
B) latent energy in the battery. 
C) the resistance of the battery to a change in polarity. 
D) electrons already in the wire. 
E) the electric field between the battery terminals. 
A) the sudden collapse in the magnetic field. 
B) latent energy in the battery. 
C) the resistance of the battery to a change in polarity. 
D) electrons already in the wire. 
E) the electric field between the battery terminals. A

Question 2

Use the following figure to answer the question:  
-A step-up transformer has a ratio of one to ten.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 these 
A) 1 W. 
B) 10 W. 
C) 100 W. 
D) 1000 W. 
E) none of these C

Question 3

Power is transmitted at high voltages because the corresponding current in the wires is

Accepted Answer

A) also high to deliver appreciable power to distant places. 
B) low so that overheating of the wires is minimized. 
C) Choices A and B are both true. 
D) Choices A and B are both false. 
A) also high to deliver appreciable power to distant places. 
B) low so that overheating of the wires is minimized. 
C) Choices A and B are both true. 
D) Choices A and B are both false. B

Question 4

The magnetic field strength inside a current-carrying coil will be greater if the coil encloses a

Accepted Answer

A) vacuum. 
B) wooden rod. 
C) glass rod. 
D) rod of iron. 
E) none of these 
A) vacuum. 
B) wooden rod. 
C) glass rod. 
D) rod of iron. 
E) none of these

Question 5

When a bar magnet is thrust into a coil of copper wire,the coil tends to

Accepted Answer

A) attract the magnet as it enters. 
B) repel the magnet as it enters. 
C) both of these 
D) neither of these 
A) attract the magnet as it enters. 
B) repel the magnet as it enters. 
C) both of these 
D) neither of these

Question 6

The primary of a transformer is the coil connected to

Accepted Answer

A) the load. 
B) the Internet. 
C) the power line. 
D) none of these 
A) the load. 
B) the Internet. 
C) the power line. 
D) none of these

Question 7

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 choices are correct. 
A) an electric generator. 
B) an automobile battery. 
C) a radio receiver. 
D) None of the above choices are correct.

Question 8

Four amperes of current exist in the primary coil of a transformer.The voltage across the primary coil is 110 V.What is the power output of the secondary coil?

Accepted Answer

A) 27.5 W 
B) 110 W 
C) 440 W 
D) 880 W 
E) not enough information to say 
A) 27.5 W 
B) 110 W 
C) 440 W 
D) 880 W 
E) not enough information to say

Question 9

The voltage across the input terminals of a transformer is 110 V.The primary has 50 loops and the secondary has 25 loops.The voltage the transformer puts out is

Accepted Answer

A) 25 V. 
B) 55 V. 
C) 110 V. 
D) 220 V. 
E) none of these 
A) 25 V. 
B) 55 V. 
C) 110 V. 
D) 220 V. 
E) none of these

Question 10

If the voltage produced by a generator alternates,it does so because

Accepted Answer

A) unlike a battery,it produces alternating current. 
B) the changing magnetic field that produces it alternates. 
C) alterations in the mechanical energy input. 
D) in effect it is an ac motor in reverse. 
E) the current it produces alternates. 
A) unlike a battery,it produces alternating current. 
B) the changing magnetic field that produces it alternates. 
C) alterations in the mechanical energy input. 
D) in effect it is an ac motor in reverse. 
E) the current it produces alternates.

Question 11

A certain transformer doubles input voltage.If the primary coil has 10 A of current,then the current in the secondary coil is

Accepted Answer

A) 2 A. 
B) 5 A. 
C) 10 A. 
D) 25 A. 
E) none of these 
A) 2 A. 
B) 5 A. 
C) 10 A. 
D) 25 A. 
E) none of these

Question 12

A device that transforms mechanical energy into electrical energy is a

Accepted Answer

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

Question 13

A principle difference between an MHD generator and a conventional generator is that the MHD generator

Accepted Answer

A) has no moving parts. 
B) operates more efficiently at high temperatures. 
C) Choices A and B are both true. 
D) Choices A and B are both false. 
A) has no moving parts. 
B) operates more efficiently at high temperatures. 
C) Choices A and B are both true. 
D) Choices A and B are both false.

Question 14

When there is a change 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 these 
E) none of these 
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 these 
E) none of these

Question 15

The output power of an ideal transformer is

Accepted Answer

A) greater than the input power. 
B) equal to the input power. 
C) smaller than the input power. 
D) may be any of these 
A) greater than the input power. 
B) equal to the input power. 
C) smaller than the input power. 
D) may be any of these

Question 16

Thrust a magnet into a coil of wire and the coil

Accepted Answer

A) becomes an electromagnet. 
B) has a current in it. 
C) both of these 
D) neither of these 
A) becomes an electromagnet. 
B) has a current in it. 
C) both of these 
D) neither of these

Question 17

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) burned out. 
D) none of these 
A) of low wattage. 
B) of high wattage. 
C) burned out. 
D) none of these

Question 18

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 19

A device that transforms electrical energy to mechanical energy is a

Accepted Answer

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

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) voltage in the coil. 
D) the coil's polarity. 
E) electromagnetic polarity. 
A) electric field intensity in the coil. 
B) magnetic field intensity in the coil. 
C) voltage in the coil. 
D) the coil's polarity. 
E) electromagnetic polarity.

Exam 25: Electromagnetic Induction

Disconnect a small-voltage battery from a coil of many loops of wire and a large voltage is produced by

Use the following figure to answer the question: -A step-up transformer has a ratio of one to ten.Neglecting slight losses,if 100 W of power go into the primary coil,the power coming from the secondary coil is

Power is transmitted at high voltages because the corresponding current in the wires is

The magnetic field strength inside a current-carrying coil will be greater if the coil encloses a

When a bar magnet is thrust into a coil of copper wire,the coil tends to

The primary of a transformer is the coil connected to

An electric motor is very similar to

Four amperes of current exist in the primary coil of a transformer.The voltage across the primary coil is 110 V.What is the power output of the secondary coil?

The voltage across the input terminals of a transformer is 110 V.The primary has 50 loops and the secondary has 25 loops.The voltage the transformer puts out is

If the voltage produced by a generator alternates,it does so because

A certain transformer doubles input voltage.If the primary coil has 10 A of current,then the current in the secondary coil is

A device that transforms mechanical energy into electrical energy is a

A principle difference between an MHD generator and a conventional generator is that the MHD generator

When there is a change in the magnetic field in a closed loop of wire

The output power of an ideal transformer is

Thrust a magnet into a coil of wire and the coil

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

The principal advantage of ac power over dc power is that

A device that transforms electrical energy to mechanical energy is a

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

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