Topic 7- magnetism and electro

Question 1

describe the motor effect

Answer 1

wire carrying current in magnetic field experiences a F
F is perpendicular to the current+ field
reversing current/ field -> reverses F
Used in electric motors

Question 2

explain how loud speaker works

Answer 2

current flows through a coil in a magnetic field
motor effect produces F——> moves coil
Ac current reverses= F——> coil vibrates
vibrations transfer to diaphragm= sound waves

Question 3

what rule is used to find direction F in motor effect

Answer 3

Flemings left hand rule
F bigger= accelerate/decelerate-> reduces/ increases velocity
F equal resultant 0= stays stationary/ stays constant velocity