Flashcards in Electromagnetism Deck (27):
What is magnetism?
A property is a material, meaning it will cause a force on other magnetic objects.
Give some examples of magnetic elements:
- steel (contains iron, so is magnetic)
What are magnetic field?
It is where a magnetic material will feel a force.
What ensures a strong magnetic force?
Magnetic field lines being close together.
What is the strength of magnetic field B measured in?
What is the Law of Magnets?
Opposite magnet poles attract each other, like magnet poles repel each other.
In what direction do magnetic fields travel in?
North to south.
What are domains?
A group of atoms that act like magnets.
How can domains be lined up?
By stroking the piece of iron with a magnet.
What happens when electricity flows?
It generated a magnetic field.
What is an electromagnet?
A magnet that is made by an electric current, and can be turned on and off.
Why is wire wrapped around the magnetic object?
To concentrate the magnetic field.
What is the name of a magnetic field of an electromagnet?
What can be done to alter the strength of an electromagnet?
- the number of coils of wire
- the current flowing through the wire
- the core
How is the direction of force shown?
Fleming's Left Hand Law:
F (FORCE) - points upwards
B (MAGNETIC FIELD) - points left
I (CURRENT) - points straight ahead
What is electromagnetic induction?
When a voltage is produced because a magnet has been moved into a coil of wire.
What are the two types of current?
Alternating current - when current constantly changes direction.
Direct current - when current flows in only one direction.
How is AC electricity measured?
The amplitude of the wave should be measured to give the current or voltage.
What is the purpose of contacts on a DC motor?
To stop the wires getting tangled.
What can be done to increase the speed of a motor?
- increase the number of coils on the magnet.
- use a stronger magnet.
- use a higher voltage or current.
What is needed to generate electricity with electromagnetic induction?
- a magnet
- a loop or cool of wire
What is an energy resource?
It is where energy to generate electricity comes from.
Examples of energy resources.
- fossil fuels
What is a non-renewable resource?
A resource used faster than more of it can be formed. One day, it will run out.
What is a renewable resource?
A resource that will be continually made faster that we use it.
What are motors?
An electrical machine that coverts electrical energy into kinetic energy.