Key terms
Poles
The end of a magnet and are called the North and South poles
Where is a magnetic field the strongest?
At the poles
What is current?
The rate of flow of charge
What direction does the gravitational field around a mass point?
Inwards
How do you increase the strength of an electromagnet?
Increase the current or number of turns
Gravitational field
The area around a body of mass where its force can be felt. It is invisible
What creates a magnetic force?
The interaction of 2 or more magnetic fields
What is voltage?
Energy per charge
What kind of force is always produced by a gravitational field?
Attractive
What factors affect the resistance of a wire?
Width, length, temperature and material
Field lines
We use/draw them to represent the strength and direction of the force field
How can we induce a magnetic field?
Using electricity or a permanent magnet
What direction does the electric field around a negative charge point?
Inwards
How could you increase strength of a gravitational field?
Increase the mass of an object
What is a rheostat/potentiometer.
What does it do?
A variable resistor
It changes the resistance and therefore the current
Domain
A tiny magnet
What materials can be magnetic?
Iron, Cobalt, Nickel, and Steel
What is resistance?
A measure of the opposition to current flow
What happens to the strength of a gravitational field as you get closer to the object?
It increases
What are the benefits of electromagnets?
Really strong and can be turned on and off
Induced magnet
A magnet where the domains can temporarily be lined up. It is caused/created by being in the magnetic field of another magnet
Why can iron be both magnetic and non-magnetic?
Because sometimes the domains line up and sometimes they don't
What happens to the strength of the field around a charged object as the distance away increases?
It decreases
How far away from Earth do you need to be to escape its gravitational field completely?
Infinity
How can you test in a school science lab the strength of different electromagnets?
By seeing how many paperclips they can pick up