Magnetism Flashcards
(20 cards)
What is an induced magnet?
An object that becomes magnetic when put in a magnetic field. Always causes attraction
how to plot field?
magnetic compass
Magnetic field in N/S?
Into south, out of north
How to make wire get mag field?
put current in it
Strength of a magnetic field in wire depends on
current strength
What’s a solenoid?
coiled wire that has similar magnetic field to a magnet
What increases strength in a solenoid?
iron core, number of coils, current
What is an electromagnet?
A solenoid with an iron core in it
What is the motor effect?
A wire perpendicular to two magnets will experience a force up
How does an electric motor work?
Motor effect but with a loop of wire and a split ring commutator to change current and make it spin
How does speakers work?
Solenoid with perma magnet inside and AC supply. AC switches, magnet repulse and attract, moves and make noise
What is the generator effect
loop of wire go through mag field, changes the wire’s current’s direction. no PD when no moving
When does the generator effect no work?
When the wire moves along the magnetic field
How do you make an induce PD larger?
if wire coiled, if move rapidly, if strong mag field
why does doing work switch poles?
The wire will always oppose movement of magnet.
How does alternator work?
Produce AC via changes of direction in a generator
What’s a dynamo?
Generator with split ring commutator produces DC
How does a moving coil microphone work
soundwaves cause diaphragm to vibrate, wire move through feild
why do transformers only work with AC?
Need a change in mag field for PD
How do transformers work?
solenoids on an iron core, and changing mag field passes through core and produce PD
