Topic 7-Magnestism and electromagnetism Flashcards
(31 cards)
What are the two poles?
North and south.
What do all magnets produce?
A magnetic field.
Where is the magnetic field strongest on a magnet?
At the poles.
The closer magnetic field lines are …
The stronger the magnetic field.
Which direction do magnetic field lines always go?
From north to south.
What forces can magnets experience?
Attraction or repulsion.
North and a North?
Repulsion.
South and a North?
Attraction.
What device shows the direction of magnetic field lines?
A compass.
What are the two types of magnets?
Permanent and induced.
What is a permanent magnet?
A magnet that can produce its own magnetic field.
What are induced magnets?
Magnetic materials that turn into a magnet when they are put into a magnetic field.
What is the force between permanent and induced magnets?
Attraction.
What happens when a current flows through a wire?
A magnetic field is created around the wire.
How can you increase the strength of the magnetic field that a wire produces?
By wrapping the wire into a coil.
What is the coil called that you wrap around a wire to increase the magnetic field?
A solenoid.
What is a solenoid with an iron core called?
An electromagnet.
What can electromagnets be used for?
To pick stuff up with a crane.
What is the equation for force?
Magnetic flux density x current x length.
What is the generator effect?
The induction of a potential difference in a wire which is moving relative to a magnetic field, or experiencing a change in magnetic field.
What does the generator effect create?
A potential difference in a conductor.
If the conductor is part of a circuit what does the generator effect create?
A current.
what do dynamos generate?
A direct current.
What do alternators generate?
An alternating current.
