Section 6 Flashcards
What happens if you increase the electric current?
The strength of the magnetic field increases.
What four factors increase the speed in an electric motor?
More current, more turns on the coil, stronger magnetic field, a soft iron core in the coil.
How can you change the direction of the motor?
Swapping the polarity or swapping the magnetic poles.
What current is used in a motor?
DC
What current is used in a loudspeaker?
AC
In a loudspeaker what causes the coil to move back and forth?
The coil is surrounded by a permanent magnet, so the a.c. signals cause a force on the coil and make it move back and forth.
What do the movements on the coil cause?
Makes the cone vibrate and this creates sound.
What is electromagnetic induction?
The creation of a voltage in a wire which is experiencing a change in magnetic field.
How can you get a bigger voltage?
Increase the strength of the magnet, increase the number of turns on the coil, increase the speed of movement.
