Magnetism and ElectroMagnetism

Question 1

how do generators work?

Answer 1

coil spins, the wire will cut the magnetic field lines, this induces a potential difference in the wire, the induced current on each side of the coil is opposite which makes current flow through the wire

Question 2

what is a dynamo?

Answer 2

the split ring commutator changes the current through the coil every half turn, causing a direct current

Question 3

what is an alternator?

Answer 3

this doesn’t have a split ring so current changes direction, causing alternating current

Question 4

how do loudspeakers use the motor effect?

Answer 4

the alternating current in the wire creates a changing magnetic field which interacts with a permanent magnetic field, this causes force on the cone. the cone moves backwards and forwards, the air particles oscillate which creates a sound wave

Question 5

how do microphones use the generator effect?

Answer 5

a sound wave causes air particles to oscillate which causes the cone to move backwards and forwards through a magnetic field. this induces a potential difference in the wire which creates AC