Magnetism Review

Which of the following items are required to make an electromagnet?

• An iron core

• A coil of wire

• A battery

• A permanent magent

Answer explanation

An iron core makes the electromagnet work better, but is not required to make an electromagnet.

Which of the following items will make a simple electromagnet (a coil of wire attached to a battery) more effective at picking up paperclips?

• inserting an iron core inside the coil.

• attaching a voltmeter to the circuit

• using a bigger voltage battery

• inserting a pencil inside the coil

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NGSS.MS-ETS1-1

Why does a motor begin to rotate?

• The current exerts force on the wire.

• The current creates a magnetic field around the wire that gets pushed by the permanent magnet

• Someone's hand has to keep it rotating.

• The permanent magnet pulls current from the battery and that makes the dead wire move.

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This image is a metal block. Which of these statements best explains what the image is showing.

• These are magnetic domains; since they are not aligned this is a magnetic material but not a permanent magnet.

• These are magnetic domains; since they are not aligned this is NOT a magnetic material.

• These are magnetic domains; since they are not aligned this is a permanent magnet.

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NGSS.HS-PS2-5

NGSS.HS-PS3-5

Shown in the image is 2 bar magnets. What types of poles are interacting?

• 2 opposite poles

• 2 north poles

• 2 south poles

Answer explanation

Magnetic fields flow from N to S so the parallel field lines connect a N and S pole.

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Which of these changes would result in a greater induced voltage and current during magnetic induction?

• Use a coil with more loops.

• Use a coil with less loops.

• Fluctuate the magnetic field faster.

• Fluctuate the magnetic field slower.

The wire in the image is vertical and the current is flowing downward. Which direction is the magnetic field acting on the right side of the wire?

• into the screen

• out of screen

• upward

• to the left

Answer explanation

Using the R-hand rule your thumb will point in the direction of the current and your fingers show the direction of the magnetic field.

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A magnetic compass is placed near a copper wire. When the wire is connected into a battery, the compass needle changes position.  Which of the following is the best explanation for the movement of the compass needle?

• The copper wire magnetizes the needle to create a force.

• The needle magnetizes the copper wire to create a force.

• Current flows through the compass needle making it move.

• The current in the wire creates a magnetic field that exerts a force on the compass needle.

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NGSS.MS-PS2-5

Which of the following items are required to make a motor?

• An iron core

• A coil of wire

• A battery

• A permanent magent

Tags

NGSS.MS-ETS1-1

Choose which similarity and which difference applies for electric charges and magnetic poles.

• Difference: charges can attract or repel but magnetic poles only attract

• Difference: you can separate charges but you can't separate magnetic poles

• Similarity: charges and magnetic poles can attract or repel

• Similarity: you can separate charges and magnetic poles