Study Guides

Unit Summary

This unit explores magnetism, including permanent and induced magnets, magnetic fields, and Earth's magnetism. It covers current-induced magnetic effects, electric motors, and devices like microphones and loudspeakers, with an emphasis on models, calculations, and practical applications.

Lesson Summary

You will learn to describe how to test the strength of an electromagnet.

Key Notes

• When there is an electric current in a wire, there is a magnetic field around the wire.
• An electromagnet is a magnet that can be turned on with an electric current, and turned off.
• The magnetic field of an electromagnet is similar to the field around a bar magnet.
• A soft iron core in an electromagnet becomes magnetised and adds to the strength of field when the electromagnet is on.
• When there is an electric current in a coil of wire, the magnetic field around each loop adds to make a stronger field.

Vocabulary To Learn

• coil of an electromagnet: is an insulated wire wound into the shape of a spring.
• turn of wire: is a single loop of wire in a coil.
• soft iron: is very pure iron that cannot be made into a permanent magnet.
• directly proportional to: describes the relationship between two variables, in which doubling the value of one variable doubles the value of the other.
• error bars: show the uncertainty of each measurement on a graph.

Common Mistakes To Avoid

• A magnetic field is the same as the electric field around a charged object.

3 Quick Questions (With Answers)

More Lessons In This Unit

• An electric motor Study Guide
• Applications of electromagnets Study Guide
• Applications of motor and generator effects Study Guide
• Electric generators Study Guide
• Plotting magnetic fields Study Guide
• Strength of an electromagnet Study Guide
• The generator effect Study Guide
• The motor effect Study Guide