Question 1

Faraday's law was extended by Maxwell toward

Accepted Answer

A) changes in electric fields. 
B) changes in magnetic fields. 
C) both of these 
D) neither of these 
A) changes in electric fields. 
B) changes in magnetic fields. 
C) both of these 
D) neither of these

Question 2

The amount of current produced by electromagnetic induction depends on the

Accepted Answer

A) amount of induced voltage. 
B) resistance of the circuit to which it is connected. 
C) both of these 
D) neither of these 
A) amount of induced voltage. 
B) resistance of the circuit to which it is connected. 
C) both of these 
D) neither of these

Question 3

Neon signs require about 12,000 volts to operate. If the circuit uses a 120-volt power source, the ratio of primary to secondary turns on the transformer should be

Accepted Answer

A) 1 primary to 100 secondary. 
B) 100 primary to 1 secondary. 
C) neither of these 
A) 1 primary to 100 secondary. 
B) 100 primary to 1 secondary. 
C) neither of these

Question 4

If the primary of a transformer is connected to a dc power source, the transformer would have a voltage output

Accepted Answer

A) at a higher efficiency than with an ac source. 
B) the same. 
C) that is also dc. 
D) only while being connected or disconnected. 
E) none of the above 
A) at a higher efficiency than with an ac source. 
B) the same. 
C) that is also dc. 
D) only while being connected or disconnected. 
E) none of the above

Question 5

Compared to the primary voltage, the secondary voltage can be

Accepted Answer

A) higher. 
B) lower. 
C) the same. 
D) any of the above 
E) none of the above 
A) higher. 
B) lower. 
C) the same. 
D) any of the above 
E) none of the above

Question 6

A friend says that changing electric and magnetic fields underlie the production of light.

Accepted Answer

A) agree with your friend 
B) argue to the contrary with your friend. 
C) find a new friend. 
A) agree with your friend 
B) argue to the contrary with your friend. 
C) find a new friend.

Question 7

If you drop a bar magnet in a vertical copper pipe it will fall slowly because

Accepted Answer

A) of air resistance. 
B) it induces a magnetic field in the pipe that resists motion of the magnet. 
C) the copper is a good conductor of both electricity and magnetism. 
D) of electron repulsion. 
A) of air resistance. 
B) it induces a magnetic field in the pipe that resists motion of the magnet. 
C) the copper is a good conductor of both electricity and magnetism. 
D) of electron repulsion.

Question 8

A device that transforms mechanical energy into electrical 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 9

When voltage is stepped up in a transformer, current is stepped down. But Ohm's law tells us that greater voltage means greater current, not less current. How then can current be lower when voltage is increased?

Accepted Answer

A) Current in the secondary is lower when compared to the greater current drawn by the primary. 
B) Ohm's law applies to the circuit connected to the secondary, not to the transformer. 
C) both of these 
D) neither of these 
A) Current in the secondary is lower when compared to the greater current drawn by the primary. 
B) Ohm's law applies to the circuit connected to the secondary, not to the transformer. 
C) both of these 
D) neither of these

Question 10

Disconnect a small-voltage battery from a coil of many loops of wire and a large voltage may be 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.

Exam 25: Electromagnetic Induction

Faraday's law was extended by Maxwell toward

The amount of current produced by electromagnetic induction depends on the

Neon signs require about 12,000 volts to operate. If the circuit uses a 120-volt power source, the ratio of primary to secondary turns on the transformer should be

If the primary of a transformer is connected to a dc power source, the transformer would have a voltage output

Compared to the primary voltage, the secondary voltage can be

A friend says that changing electric and magnetic fields underlie the production of light.

If you drop a bar magnet in a vertical copper pipe it will fall slowly because

A device that transforms mechanical energy into electrical energy is a

When voltage is stepped up in a transformer, current is stepped down. But Ohm's law tells us that greater voltage means greater current, not less current. How then can current be lower when voltage is increased?

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

About Science

Newtons First Law of Motion: Inertia

Linear Motion

Newtons Second Law of Motion

Newtons Third Law of Motion: Action and Reaction

Momentum

Energy

Rotational Motion

Gravity

Projectile and Satellite Motion

Atomic Nature of Matter

Solids

Liquids

Gases and Plasmas

Temperature, Heat, and Expansion

Heat Transfer

Change of Phase

Thermodynamics

Vibrations and Waves

Sound

Musical Sounds

Electrostatics

Electric Current

Magnetism

Properties of Light

Color

Reflection and Refraction

Light Waves

Light Emission

Light Quanta

The Atom and the Quantum

Atomic Nucleus and Radioactivity

Nuclear Fission and Fusion

Special Theory of Relativity

General Theory of Relativity

Systems of Measurement

Filters