P13 - Electromagnets Flashcards
What are the 4 magnetic materials?
Iron
Steel
Cobalt
Nickel
What are the forces between poles?
LIKE poles REPEL
UNLIKE poles ATTRACT
What is a magnetic field?
Region around a magnet
What is induced magnetism?
When an unmagnetised magnetic material can be magnetised by placing it in a magnetic field
What does a magnetic field cause?
A force of attraction between any unmagnetised material placed at one end of a bar magnet and always attractive at whichever end
What is a solenoid?
Long coil of insulated wire needed for strong magnetic fields
What happens to the strength of the force if current in the solenoid increases?
Strength of the force will increase
What is the difference inside and outside of the solenoid?
Inside - Field is strong and uniform
Outside - field lines pass through solenoid
Define an electromagnet?
Solenoid where insulated wire is wrapped around iron bar - core - current is passing meaning iron bar is magnetised
What happens when force acts upon a wire in a magnetic field?
Current is passed through the wire
What does the size of the force increasing do?
Increases current
Using a stronger magnet
When is force at its greatest and zero in terms of wire direction?
Greatest - wire perpendicular to magnetic field
Zero - wire is parallel to field lines
What does magnetic flux density measure?
Strength of magnetic field
What is the equation for magnetic flux density?
Force = magnetic flux density X current X length
What is the rule needed to learn?
Flemings left hand rule
