U2L4 Electromagnetism Study Guide

Also study Book pages, Notes, Electromagnet Lab, and Simple Circuit Lab

The rate at which electric charges move THROUGH a wire in a closed circuit  is called what?

Electric current

What is the unit for current?

Ampere (A)

What is the unit for voltage?

Volt (V)

Resistance is measured in

Ohms ( Ω )

If voltage is increased, current will

increase

If resistance increases, the current will

decrease

Resistance in a really skinny wire could produce

heat

What is Ohm’s Law?

Current (I) = Voltage (V) / Resistance ( R )

What is created around the outside of a wire when electric current is flowing through the wire?

A magnetic field is generated.

What are 3 ways to increase the strength of an electromagnet?

Increase the current, increase the # of coils, add an iron core. 

The electric motor converts electrical energy into what kind of energy?

Kinetic energy

The electric generator converts kinetic energy into what kind of energy?

Electrical energy

The electric generator generates an electric current by moving a coil of wire inside a permanent magnet.  What is the name of this process?

Electromagnetic induction

The magnetic field of an electromagnet can be easily reversed by doing what?

Reversing the current that flows through the coil.

A compass has a magnetic needle.  So what would happen if a wire with current flowing through it was brought near it?

The compass would wiggle because the current in the wire would create a magnetic field and the magnetic needle of the compass would react to it.

In the electric motor, why does the electromagnet spin inside the permanent magnet?

The electromagnet spins to line up with the opposite poles of the permanent magnet.

What are 3 ways to increase the current produced by a generator?

1.  Spin it faster

2. Increase the number of coils

3. Increase the strength of the magnets

What part in the motor is used to reverse the current quickly?

Commutator

Magnetic force can be either

attract and repel

For an object to be magnetic it must have the ______ _______ lined up.

magnetic domains

If magnetic poles are opposite and then are placed next to each other will be

attract

If magnetic poles are the same and are placed next to each other will be

repel

Why does a compass needle point to the Earth’s geographic north pole?

The earth’s magnetic poles are located near there.

Electric forces can be either

attract or repel

If an object has an even number of positive and negative charges, its net charge will be

neutral

If an object has more positive charges than negative charges, its net charge will be

positive

If an object has more negative charges than positive charges, its net charge will be

negative

When charges move from one subject to another