Magnetism and Electromagnetism Flashcards
Where is the force strongest at on a bar magnet?
At each of the poles.
Is magnetic attraction and repelling a contact or a non contact force?
Non-contact
What is a permanent magnet?
A permanent magnet always has a magnetic field around it. It can attract and repel other magnets.
What is an induced magnet?
An induced magnet only becomes magnetic once placed in the magnetic field. It can attract other metals but cannot repel them. They also lose magnetism quickly.
How can you increase the strength of an electromagnet? (give three ways)
Increasing the current
Increasing the number of coils
Inserting an iron core
What does FBI stand for when talking about magnetism?
Force
B-Magnetic field
I-Current
How frequently does the split ring commutator change the current?
Every half rotation
What direction does the split ring commutator move in?
Anti-clockwise
When is the direction of the induced current reversed?
The wire is moved in the opposite direction
The field is reversed
What can increase the size of the induced current?
When the speed of the movement is increased
When you increase the magnetic strength
The amount of turns on the coil is increased
What are the 4 ways that current can be increased in an AC generator?
Increasing the speed of the movement
Increasing the magnetic field strength
Increasing the area of the coil
Increasing the number of turns on the coil.
How does a Diaphragm move in a microphone?
The pressure vibrations from the sound waves
What does the coil in a microphone move in relation to?
The coil moves in relation to the magnetic field, inducing a current through the wire.
What does DC stand for?
Direct current
What does AC stand for?
Alternating current
