Name:

# Electromagnetic Force Fill-in

There are four force field in nature:

```    1.                                              3.
2.                                              4.
```

## The Electromagnetic Force

1. Acts on ________________ _________________ in an electromagnetic (EM) field.
2. The EM field has both an _________________ and _________________ field.
3. A changing ________________ field produces a ________________ field.
4. A changing magnetic ________________ creates an electric ________________.

## Manifestations

1. Electromagnets - An electric ________________ moving in a wire generates a ________________field. We often coil the wire to increase the strength of the magnetic field.
2. Permanent magnets - A magnetic force field can be generated by the ________________ of a particle's ________________. Iron, nickel and ________________ are common magnetic materials.
1. A ________________ has a magnetized needle that is free to move. The Earth core produces a magnetic field. The compass's magnet interacts with the Earth's magnetic field. Note the Earth's ________________ north pole is the Earth's ________________ south pole!
3. ________________ use either electromagnets or permanent ________________ to create a magnetic ________________ . Electricity following in ________________ of wires generates an ________________ magnetic field. The feuding ________________ cause the motor ________________ to ________________ .
4. ________________ use either electromagnets or permanent magnets to create a magnetic field. Spinning the wire coils attached to the generator's rotor causes electricityto flow.

## Useful Parts

1. ________________ are made of metals such as copper. Metallic elements have electrons that are not held close to the element's atoms. It is as if there was a cloud of electrons around the atoms. This allows the electrons to move easily and thus the metal conducts electricity. Insulators do not have these highly mobile electrons and so do not conduct - they stop the flow of electricity.
2. Lamps are a wire in a vacuum or inert gas enclosed by a glass envelope. The wire material, typically tungsten , gets white hot when enough electricity flows through it. The electricity may flow either direction through the lamp. The lamp is pretty tough - it can handle small amounts of too much voltage. Note: a light emitting diode (LED ) is a completely different technology. Electricity can only flow one direction in an LED. Reverse connections or too much voltage will destroy it instantly.
3. A cell is a device that derives electrical energy from chemical reactions. There are several different chemistries possible depending on the amount of electricity needed and the costs. More than one cell connected together is called a battery . A rechargeable cell has a reaction that can run backwards by adding electricity!