Electricity and Magnetism

Electricity and Magnetism

1. Objects can be charged positively or negatively by transforming electrons.

2. Like charges repel and unlike charges attract.

3. An electric field is a region where there is a force on charged particles or materials.

4. Electric current is the amount of charge flowing per second. You measure current in amps (A) using an ammeter.

5. The potential difference of a cell tells you the size of the push on the charges and how much energy can be transferred by them.

6. You measure potential difference in volts (V) using a voltmeter. The rating of a cell or battery tells you the potential difference at which it operates.

7. Series circuits contain only one loop, and the current is the same everywhere. Parallel circuits have branches and the currents in all the branches add up to the total current.

8. A component with a high resistance has a small current through it. Resistance is measured in ohms(__) You calculate the resistance using potential difference across a component and the current through it. Insulators have a very high resistance and conductors have a very low resistance.

9. Magnets have a north pole and a south pole. Like poles repel and unlike poles attract.

10. Magnetic materials feel a force in the region around a magnet called a magnetic field.

11. A current flowing in a coil of wire wrapped around a magnetic material is an electromagnet. It behaves like a bar magnet, but you can turn it on and off.

12. Electromagnets are used in maglev trains, hospitals and cars.

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