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Skills Worksheet
Section Review p.522
Magnetism from Electricity
USING KEY TERMS
For the pair of terms, explain how the meanings of the terms differ.
1. electromagnet and solenoid
An electromagnet is a solenoid that has an iron core, so an electromagnet has a stronger magnetic
field than the solenoid has.
3. Describe what happens when you hold a compass close to a wire carrying a
current.
The needle may deflect and not point north.
5. What makes the armature in an electric motor rotate?
The motor’s magnet exerts a force (up on one side, down on the other) on the armature, which causes
the armature to rotate.
Section Review continued
7. Making Comparisons Compare the structures and magnetic fields of solenoids
with those of electromagnets.
A solenoid is a coil of wire that carries electric current. An electromagnet is a solenoid that has an
iron coil. An electromagnet has a stronger magnetic field than the solenoid has.
Interpreting Graphics
8. Look at the image in your textbook for this Section Review. Your friend says
that the image shows an electromagnet because there are loops with a core in
the middle. Is your friend correct? Explain your reasoning.
Possible answer: The friend is wrong. The loops of an electromagnet must be loops of wire, not ring
magnets. The core of an electromagnet must be made of iron. The core in the image is a pencil.
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Holt Science and Technology
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Electromagnetism