magnetism p2

Question 1

induced magnet

Answer 1

only becomes it when placed in a magnetic field

Question 2

4 magnetic materials

Answer 2

iron, steel, nickel, cobalt

Question 3

larger current=

Answer 3

stronger magnetic field

Question 4

ways to increase strength of current/magnetic field

Answer 4

1)increase size of current/magnetic field
2)increase no of turns
3)add an iron core

Question 5

electromagnet?

Answer 5

solenoid with an iron core

Question 6

if current is parallel to magnetic field

Answer 6

no force experienced

Question 7

when changing direction of current

Answer 7

direction of magnet changes (polarity)

Question 8

motor effect

Answer 8

when a current carrying conductor is placed in a magnetic field, it experiences a force.

Question 9

how motors work

Answer 9

1)current carrying coil in magnetic field rotates
2)brush is connected to commutator-current in coil is always in same direction
3)coil continues to rotate not just stop

Question 10

how loudspeakers work

Answer 10

1)current flows into coil
2)current and mf interact- coil moves
3)cone moves
4)vibrations occur-sound

Question 11

generator effect

Answer 11

motion of wire thru magnetic field causes a current to pass thru wire.

Question 12

induced pd

Answer 12

caused by cutting thru magnetic field lines

Question 13

how alternators work

Answer 13

1)1 side of coil moves up thru mf
2)pd induced in 1d
3)as coil moves down,pd reverses direction-AC formed

Question 14

how dynamos work

Answer 14

same as alternators but with a split ring commutator- changes coil connections every half turn- DC formed

Question 15

how microphones work

Answer 15

1)sound waves make diaphragm vibrate
2)coil vibrates
3)pd induced in the coil
4)current flows round circuit
5)

Question 16

whats a transformer made up of

Answer 16

1)primary coil, secondary coil (wire)
2)wrapped around an iron core- easily magnetised