Unit Test — Unit test Answers

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Mateo makes a table of the symbols that represent the parts of an electric circuit.

Question illustration
A
Uses electrical energy
B
Provides electrical energy
C
Measures electric current
D
Controls electric current
2
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Which device manages the flow of current in an electric circuit?

A
the wire
B
the switch
C
the battery
D
the light bulb
3

What happens to an iron bar when it is placed within the coils of a solenoid?

A
It induces a current.
B
It stops the current.
C
It becomes a magnet.
D
It loses its magnetism.
4

Georgia moves an unattached piece of wire back and forth over a magnet. Which best explains what will happen?

A
A current will be induced because the wire moves through a magnetic field.
B
A current will not be induced because the wire moves through a magnetic field.
C
A current will be induced because the wire is not part of a closed circuit.
D
A current will not be induced because the wire is not part of a closed circuit.
5

Nina is working with electricity and shortens the wires through which the current is flowing. What is Nina most likely trying to accomplish?

A
convert electric energy to heat
B
convert electric energy to light
C
increase resistance
D
decrease resistance
6

Aretha measures a circuit at 110 V and 240 . Using Ohm’s law, what can she calculate for the circuit?

Question illustration
A
voltage
B
ohms
C
resistance
D
current
7

How does increasing the distance between charged objects affect the electric force between them?

A
The electric force increases because the distance has an indirect relationship to the force.
B
The electric force increases because the distance has a direct relationship to the force.
C
The electric force decreases because the distance has an indirect relationship to the force.
D
The electric force decreases because the distance has a direct relationship to the force.
8

The image shows the electric field lines around two charged particles.

Question illustration
A
1
B
2
C
3
D
4
9

What is required for an electric charge to flow through a wire?

A
zero resistance in the wire
B
a balance of electric potential
C
high resistance in the wire
D
a difference in electric potential
10

Ohm’s law describes the relationship between which quantities?

A
voltage, resistance, and ohms
B
resistance, current, and amperes
C
current, voltage, and resistance
D
amperes, ohms, and current
11

Which statement correctly describes Earth’s magnetic field?

A
A compass can lead a hiker to the geographic North Pole.
B
The magnetic pole near the South Pole is a north pole.
C
Compasses point toward a magnetic pole that is a north pole.
D
Field lines circle Earth from east to west.
12

A bar magnet is cut in half, as shown. Which shows the pieces after the magnet is cut?

Question illustration
A
2 pieces of broken magnet with a jagged edge on the inside side of each piece. On the left a piece labeled N S from left and on the right a piece labeled N S from left.
Option A
B
2 pieces of broken magnet with a jagged edge on the inside side of each piece. On the left a piece labeled N S from left and on the right a piece labeled S N from left.
Option B
C
2 pieces of broken magnet with a jagged edge on the inside side of each piece. On the left a piece labeled N and on the right a piece labeled S.
Option C
D
2 pieces of broken magnet with a jagged edge on the inside side of each piece. On the left a piece labeled S and on the right a piece labeled N.
Option D
13

What is the resistance of a clock if it has a current of 0.30 A and runs on a 9.0-V battery?

A
0.033
Option A
B
2.7
Option B
C
9.3
Option C
D
30
Option D
14

What is an advantage of series circuits?

A
Adding more batteries will increase the current.
B
There is more than one path for charges to flow.
C
If one bulb goes out, the other bulbs still shine.
D
Light bulbs get dimmer as more bulbs are added.
15

In a movie, a character cuts a wire, which stops the countdown timer of a bomb. What does cutting the wire do to the circuit?

A
It opens the circuit so that electric charges do not flow to the timer.
B
It closes the circuit so that electric charges do not flow to the timer.
C
It opens the circuit so that electric charges flow to the timer.
D
It closes the circuit so that electric charges flow to the timer.
16

The diagram shows a coiled wire that carries an electrical current.

Question illustration
A
the magnetic field
B
thermal energy
C
light energy
D
the electric field
17

An object that is made of which material is likely to be attracted to a magnet?

A
nitrogen
B
nickel
C
paper
D
plastic
18

Tisa makes a diagram to organize her notes about charging objects.

Question illustration
A
Electrons move between objects.
B
The objects do not touch.
C
The objects develop opposite charges.
D
The objects have the same charge.
19

Frances drew a diagram to show electromagnetic induction.

Question illustration
A
Current
B
Magnetic field
C
Solenoid
D
Force on wire
20

Which will a positively charged object attract?

A
an object that has a negative charge
B
an object that has a smaller positive charge
C
an object that has no charge
D
an object that has a larger positive charge

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