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Applications of Electromagnetic Induction Answers

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The voltage across the primary winding is 350,000 V, and the voltage across the secondary winding is 17,500 V. If the secondary winding has 600 coils, how many coils are in the primary winding?

A
30 coils
B
583 coils
C
12,000 coils
D
332,500 coils
2
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The voltage across the secondary winding is 10,000 V, and the voltage across the primary winding is 25,000 V. If the primary winding has 200 coils, how many coils are in the secondary winding?

A
50 coils
B
80 coils
C
125 coils
D
500 coils
3

The voltage across the primary winding is 350,000 V, and the voltage across the secondary winding is 17,500 V. If the secondary winding has 600 coils, how many coils are in the primary winding?

A
30 coils
B
583 coils
C
12,000 coils
D
332,500 coils
4

Which best describes what happens in an electric generator?

A
Motion causes constantly changing magnetic fields to induce electrical energy.
B
Motion causes constantly changing magnetic fields to induce kinetic energy.
C
Constantly changing magnetic fields lead to motion, which induces electrical energy.
D
Constantly changing magnetic fields lead to motion, which induces kinetic energy.
5

Which is an important step in how an electric motor uses magnetic force to produce motion?

A
As the north pole of the electromagnet nears the north pole of the permanent magnet, the current reverses and the poles of the magnets then attract.
B
As the north pole of the electromagnet nears the south pole of the permanent magnet, the current reverses and the poles of the magnets then repel.
C
As the north pole of the electromagnet nears the north pole of the permanent magnet, the current reverses and the poles of the magnets then repel.
D
As the north pole of the electromagnet nears the south pole of the permanent magnet, the current reverses and the poles of the magnets then attract.
6

Keiko builds a transformer in the lab, but it does not decrease the voltage as much as she needs. What should Keiko change to further reduce the voltage?

A
She should make the number of coils in the primary winding less than in the secondary winding.
B
She should make the number of coils in the primary winding the same as in the secondary winding.
C
She should increase the number of coils in the secondary winding.
D
She should increase the number of coils in the primary winding.
7

In a step-down transformer, which describes the primary winding compared with the secondary winding?

A
higher voltage and fewer coils of wire
B
higher voltage and more coils of wire
C
lower voltage and fewer coils of wire
D
lower voltage and more coils of wire
8

Which device converts electrical energy into kinetic energy?

A
an electric generator
B
an electric motor
C
a step-down transformer
D
a step-up transformer
9

Which component is found only in electric generators and not in electric motors?

A
a commutator
B
brushes
C
an armature
D
slip rings
10

The diagram shows an electric motor.

Question illustration
A
W
B
X
C
Y
D
Z
11

The diagram shows a simple electric generator that Keisha is studying.

Question illustration
A
It will move to a large positive value and stay there.
B
It will move back and forth between 0 and a large positive value.
C
It will move back and forth between a large positive and a large negative value.
D
It will move to a large negative value and stay there.
12

The voltage across the primary winding is 6000 V. If the primary winding has 50 coils and the secondary winding has 20 coils, what is the secondary voltage?

A
120 V
B
2400 V
C
15,000 V
D
120,000 V
13

[BLANK]

A
brush
B
transformer
C
commutator
D
armature
14

How does an electric generator work?

A
The axle rotates the armature in the magnetic field of a permanent magnet, which induces an electric current.
B
The armature rotates the axle in the magnetic field of a permanent magnet, which induces an electric current.
C
The axle rotates the armature in the magnetic field of an electromagnet, which induces an electric current.
D
The armature rotates the axle in the magnetic field of an electromagnet, which induces an electric current.
15

In a step-down transformer, which describes the primary winding compared with the secondary winding?

A
higher voltage and fewer coils of wire
B
higher voltage and more coils of wire
C
lower voltage and fewer coils of wire
D
lower voltage and more coils of wire
16

How does an electric motor use magnetic force to produce motion?

A
The north pole of a permanent magnet placed in the center of an electromagnet attracts the north pole of the electromagnet.
B
The north pole of an electromagnet placed in the center of a permanent magnet attracts the north pole of the permanent magnet.
C
The north pole of a permanent magnet placed in the center of an electromagnet repels the north pole of the electromagnet.
D
The north pole of an electromagnet placed in the center of a permanent magnet repels the north pole of the permanent magnet.
17

Elena makes a table to organize the functions of electric motor components.Which functions belong in the cells marked X and Y?

Question illustration
A
X: Conducts current to the armature and reverses direction of currentY: Rotates as a result of changing magnetic forces
B
X: Rotates as a result of changing magnetic forcesY: Conducts current to the armature and reverses direction of current
C
X: Allows current to flow into the commutatorY: Conducts current to the armature and reverses direction of current
D
X: Allows current to flow into the commutatorY: Rotates as a result of changing magnetic forces
18

What parts are found in an electric generator? Select 4 options.

A
an armature
B
a battery
C
a permanent magnet
D
an electromagnet
E
brushes
F
slip rings
19

Which best describes the steps involved in the operation of an electric generator?

A
The electric current passes from the power source, through the brushes, and into the commutator.
B
The electric current passes from the brushes, through the slip rings, and to the collection device.
C
The electric current passes from the slip rings, through the brushes, and to the collection device.
D
The electric current passes from the commutator, through the brushes, and into the power source.
20

Roberto plans to use two transformers to reduce a voltage of 120 V to 4 V. He uses a transformer that has 300 coils in the primary winding and 50 coils in the secondary winding. He has four other transformers, as listed in the table.Which transformer should Roberto use to have an ending voltage of 4 V?

Question illustration
A
W
B
X
C
Y
D
Z

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