Section 10 - Magnetism And The Motor Effect Flashcards
What does the strength of a magnetic field depend on?
The size of the current
If a current is strong, does this make the magnetic force stronger or weaker?
Stronger
When is the magnetic field the strongest?
When it’s closer to the wire, and it gets weaker with increasing distance
What is a solenoid?
Wires made into a coil
What do the magnetic field from all parts of a coiled wire form?
An overall magnetic field, magnetic field inside the solenoid is almost uniform near the centre on the coil
What do the fields from the individual coils form?
A very strong field inside the solenoid
Why are there weaker fields on the outside of a solenoid?
Because the fields from once side to the other side of the coil tend to cancel out
What is an electromagnet?
A coil of wire with a current flowing through it
How can you make the magnetic field of an electromagnet stronger?
By putting a piece iron inside the coil
How does putting a piece of iron through an electromagnet make the magnetic field stronger?
The iron becomes a temporary magnet - only magnetic will the field from the electromagnet is affecting it
How can you make an electromagnet stronger?
By wrapping the coil around a piece of iron / wrapping round more coils / increasing current flow through the coils
Why is there a limit to how much current can safely be passed through a wire?
Because the resistance of the wire will cause heating
What is an advantage to electromagents rather than permanent magnets?
They can be turned on and off / the strength of the magnetic field can be varied
What is the motor effect.
A length of wire moving when in a magnetic field and a a
DC current being passed through it
Why is there an electric forcefield around a wire?
Because the current creates a magnetic field and the wire interacts with the magnetic field between the magnets
