Answer Key: Review Vocabulary Words | PDF | Magnet | Magnetism - Free Printable

The image you've uploaded is an answer key for a Unit 11 Magnets Review worksheet. It includes answers to vocabulary and conceptual questions about magnets, electromagnets, magnetic fields, and related topics. Below is a detailed explanation of each answer, to help understand the reasoning behind them:

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1. What would happen if the north pole of a magnet was held near another north pole?

Correct Answer: b. The poles would repel

Explanation:
Magnetic poles follow a simple rule: like poles repel, opposite poles attract. So, when two north poles are brought close together, they will push away from each other due to repulsive magnetic forces.

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2. Where is a magnet the strongest?

Answer: At the poles

Explanation:
The magnetic field is strongest at the poles (north and south) of a magnet. This is where the magnetic field lines are most concentrated. The field weakens as you move toward the center (middle) of the magnet.

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3. Name three materials that magnets are attracted to.

Answers:
a. Iron
b. Cobalt
c. Nickel

Explanation:
These three metals are ferromagnetic, meaning they can be strongly attracted to magnets and can themselves become magnetized. They have unpaired electrons that align under a magnetic field, creating attraction.

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4. Name three ways an electromagnet is different from a bar magnet.

Answers:
a. Electromagnets can be turned off
b. The polarity (poles) can change in an electromagnet
c. You can alter (change) the strength of an electromagnet

Explanation:
- Electromagnets are created by electric current flowing through a coil of wire. When the current stops, the magnetic field disappears → can be turned off.
- Reversing the direction of current reverses the magnetic poles → polarity can change.
- Increasing current or number of coils increases magnetic strength → strength is adjustable.

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5. What is a solenoid?

Answer: A coil of wire with an electric current in it

Explanation:
A solenoid is a long coil of wire, often wrapped around a core (like iron). When electric current flows through it, it generates a uniform magnetic field inside the coil — essentially acting like a bar magnet. Solenoids are used in electromagnets and actuators.

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6. Which process occurs when a paper clip is held near a magnet? Explain what happens to the paper clip.

Answer:
*The paper clip is drawn towards the magnet by the magnetic field. The domains become aligned and the paper clip becomes a temporary magnet.*

Explanation:
The paper clip is made of iron, which is ferromagnetic. When placed near a magnet:
- The magnetic field causes the magnetic domains (tiny regions of aligned atoms) in the iron to align with the external field.
- This turns the paper clip into a temporary magnet.
- Since opposite poles now face each other, the paper clip is attracted to the permanent magnet.

This is called induced magnetism.

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7. What are two ways you can increase the strength of an electromagnet?

Answers:
a. Add a bigger energy source (e.g., higher voltage/current)
b. Add more coils (turns of wire)

Explanation:
- More current increases the magnetic field strength because the magnetic field is directly proportional to current.
- More coils mean more loops contributing to the magnetic field → stronger overall field.
Other factors include using a soft iron core (which concentrates the field), but these two are listed here.

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8. Name the four types of magnet and choose two types to describe.

Types:
a. Ferromagnet
b. Electromagnet
c. Temporary Magnet
d. Permanent Magnet

Descriptions:
- Ferromagnet: Magnets made of iron, nickel, cobalt, or their mixtures. These materials can retain magnetism and are strongly attracted to magnets.
- Electromagnet: A magnet created by electric current flowing through a coil (usually around an iron core). Its magnetic field can be turned on/off and adjusted.

Additional Notes:
- Temporary Magnet: Made from materials like soft iron that become magnetic only while in a magnetic field; lose magnetism quickly once removed.
- Permanent Magnet: Made from materials like alnico or neodymium that retain their magnetism over long periods.

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✔ Summary of Key Concepts:

- Poles: Like poles repel, unlike attract.
- Magnetic Materials: Iron, cobalt, nickel.
- Electromagnets: Controllable, temporary, powered by electricity.
- Solenoids: Coiled wires that act as magnets when energized.
- Induced Magnetism: Objects like paper clips become temporary magnets near strong magnets.
- Strength Control: Increase current or number of coils to strengthen electromagnets.
- Types of Magnets: Based on material, permanence, and method of creation.

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This answer key serves as a review guide for students learning about magnetism. Each answer reinforces fundamental physics concepts related to magnetism and electromagnetic principles.