science Unit 3 lesson 2

resistor

objects that resist the flow of electric current

electromagnetic

a magnet formed when electric current flows through wire, wrapped din coils around an iron bar

motor

a device that changes electricity to other forms of energy into mechanical energy

generator

a device that produces alternating current by spinning an electric coil between the poles of a magnet; changes motion into electrical energy

What does a resistor do?

objects that assist the flow of electric current

What does an electric motor do?

it changes electrical energy into motion

What is mechanical energy?

the energy of moving parts in a machine

What are the three parts of an electric motor?

magnet, shaft, loop of wire attached to an electricity source

What is the difference between alternating current and direct current?

alternating current flows in one direction and the flows in the opposite direction; direct current only flows in one direction

What is voltage and how is it measured?

is the strength of a power source and measured in volts

After an electric current leaves the power plant, the voltage is increased. Why?

to prevent the loss of power

After the electric current is increased, it is then decreased before it reaches the place where it is to be used. Why?

so that it is at a safe level for home use

What is a transformer?

changes the voltage of electric current