P17 Magnets and electromagnets Flashcards
When will poles of a magnet repel?
When they are the same pole
e.g N and N
When will the poles of a magnet attract?
When the poles are different
e.g N and S
In which direction to field lines always go?
From North towards South
What is a permanent magnet?
It produces its own magnetic field which is always there
What is an induced magnet?
An object that becomes magnetic when it is placed in a magnetic field
What can be used to plot the magnetic field around a magnet?
A compass
How can you increase field strength of an electromagnet?
Increase current
Increasing the number of turns of the coil
Adding an iron core.
What is a solenoid?
A cylindrical coil of wire
What is the shape of the magnetic field around a solenoid?
Same as the field lines of a bar magnet
How can you increase the magnetic field of a solenoid?
Iron core
More turns around the wire
Advantages of electromagnets
Can be turned on and off
Strength of magnet can be adjusted
What is a magnetic field?
The region of space around a magnet where a magnetic material will experience a force.
What does the distance between magnetic field lines indicate?
Strength of the field
Closer together = Stronger field
What is produced around a wire when an electric current flows through it?
A magnetic field
What does Fleming’s left hand rule show?
Relative orientation of the force, current and magnetic field for the motor effect.
