AnswersFL-2003310-Physical Science CRLab: Magnetic and Electric Fields

Lab: Magnetic and Electric Fields — Unit test Answers

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What does voltage describe?

A
how fast current can flow
B
how much current can flow
C
how much a material resists electrical flow
D
how fast a material conducts electrical flow
2
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Oran wants to model the behavior of Earth’s magnetic field when Earth’s magnetic south is near Earth’s geographic north using a ball, a bar magnet, and a compass. He designates the top of the ball as Earth’s geographic north.

Question illustration
A
Model 1
B
Model 2
C
Model 3
D
Model 4
3

How are the electric field lines around a positive charge affected when a second positive charge is near it?

A
The field lines combine with the lines around the second positive charge.
B
The field lines overlap with the lines from the second positive charge.
C
The field lines bend toward the second positive charge.
D
The field lines bend away from the second positive charge.
4

Based on illustrations of magnetic field lines, where could an object be placed so it would not experience a magnetic force?

A
halfway between the like poles of two magnets, because the field lines bend away and do not enter this area
B
halfway between the opposite poles of two magnets, because the field lines are the closest together
C
above the middle of a bar magnet, because the magnetic field lines are only found around the sides of the magnet
D
above a pole of a bar magnet, because the magnetic field lines either go in or go out at the end
5

What must be true in order for magnetism to induce an electric current in a wire?

A
There needs to be a switch in the circuit.
B
There cannot be a switch in the circuit.
C
The wire must be part of a closed circuit.
D
The wire must be part of an open circuit.
6

Which unit is used to measure resistance?

A
volts
B
charges
C
amperes
D
ohms
7

Dr. Eriksson is working on a material called selenium. She is adding a certain number and type of atoms to the selenium, which will control its conductivity.

A
semiconductor
B
conductor
C
superconductor
D
insulator
8

Two bar magnets are held close together. When they are released, they move toward one another. Which best describes the original placement of the magnets?

A
The magnets are placed end to end with the north pole of each pointing toward the other.
B
The magnets are placed end to end with the south pole of each pointing toward the other.
C
The magnets are placed side by side with the like poles of each magnet near the other.
D
The magnets are placed side by side with the opposite poles of each magnet near the other.
9

Badri makes the table below to review the factors that affect the electric force between objects.

Question illustration
A
changing “Direct” to “Indirect”
B
changing “Indirect” to “Direct”
C
changing “Distance” to “Amount of electric charge”
D
changing “Mass” to “Amount of electric charge”
10

Look at the circuit diagram.

Question illustration
A
one
B
two
C
three
D
four
11

Horatio drew a diagram to illustrate how magnetism is produced by electric currents.

Question illustration
A
Magnetism is not produced by electric currents unless the wire is coiled.
B
The magnetic field does not continually spread outward from the wire.
C
The magnetic field is produced inside the wire, not outside of it.
D
Magnetism is only produced when a metal bar is placed near the wire.
12

Masako measures a circuit at 12 V and 2 A. Using Ohm's law, what can he calculate for the circuit?

A
resistance ()
Option A
B
resistance (O)
C
current (I)
D
current ()
Option D
13

A positively charged object is placed to the left of a negatively charged object. Which best describes how the positively charged object will move?

A
to the left, in the direction of the electric field lines
B
to the right, in the direction of the electric field lines
C
up in the direction that the field lines bend away
D
down in the direction that the field lines bend away
14

The diagram shows two charged objects, A and B.

Question illustration
A
A: positiveB: negative
B
A: negativeB: positive
C
A: negativeB: negative
D
A: positiveB: positive
15

A circuit has a current of 1.2 A. If the voltage decreases to one-third of its original amount while the resistance remains constant, what will be the resulting current?

A
0.3 A
B
0.4 A
C
1.2 A
D
3.6 A
16

Liang is working with an electrical circuit. She replaces a straight electrical wire with a coiled wire.

A
increase the strength of the magnetic field when current flows through the circuit
B
decrease the strength of the magnetic field when current flows through the circuit
C
increase the current that flows through the wire when the circuit is active
D
decrease the current that flows through the wire when the circuit is active
17

Measurements of two electric currents are shown in the chart.

Question illustration
A
Current X has a greater potential difference, and the charges flow at a slower rate.
B
Current Y has a greater potential difference, and the charges flow at a slower rate.
C
Current X has a greater potential difference, and the charges flow at a faster rate.
D
Current Y has a greater potential difference, and the charges flow at a faster rate.
18

A component of a circuit changes, as shown below.

Question illustration
A
A switch is closed, so the circuit would be incomplete and broken and the lights in the circuit would not shine.
B
A switch is closed, so the circuit would be complete and unbroken and the lights in the circuit would shine.
C
A switch is opened, so the circuit would be incomplete and broken and the lights in the circuit would not shine.
D
A switch is opened, so the circuit would be complete and unbroken and the lights in the circuit would shine.
19

Parker wound a wire around a large iron nail. He then created an electromagnet by connecting the ends of the wire to different batteries. The table shows the current he measured for each electromagnet.

Question illustration
A
Electromagnet W is the strongest.
B
Electromagnet X is weaker than electromagnet Z.
C
Electromagnet Y is the strongest.
D
Electromagnet Y is weaker than electromagnet X.
20

Which provides resistance in an electric circuit?

A
wire
B
light bulb
C
battery
D
switch

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