Chapter 15- Electromagnetism Flashcards
what are types of magnetic materials?
steel, iron, cobalt, nickel
what happens when you reverse the direction of a current?
the magnetic field reverses
what are solenoids?
long coils of wire which, when electric current is passed through them, create strong magnetic field.
the magnetic field around an electromagnet is the same as…
the one around a bar magnet
what is a permeant magnet?
when there is always a magnetic field around it, without having to pass electric current through it
what is an electromagnet?
used as cranes; very strong magnetic field. magnetic field only created when an electric current is passed through it
what is a circuit breaker?
an electrical component that interrupts a current if the levels are rising to a dangerous point, or if there is a fault in the wire
what is a relay?
a system that links to a low potential difference circuit mechanically, if a high potential difference is needed.
what is the motor effect?
current moving through a wire or coil generates a magnetic field around the wire or coil which interacts with the magnetic field of a permanent magnet which creates a force causing the wire to move
what is the generator effect?
there is the movement of the coil of wire in a magnetic field which induces potential difference which causes current to flow.
what is induced magnetism?
is magnetism created when an unmagnetised magnet material becomes magnetised because it was placed in a magnetic field
how do you increase the strength of a magnet?
more Coils, more Current a stronger iron Core
how can you increase the amount of current being produced with the generator effect?
increase strength of permanent magnet, increase the speed of rotations, increase the length of the wire
what is a split ring commutator?
It makes sure the potential difference never reverses, therefore this makes the current dc (direct current)n
what is a transformer?
used to transform the potential difference in an ac supply. they can step up or step down the potential difference. this depends on the ratio of the turns on the primary and secondary coil.
