The motor effect

Question 1

What happens when a current flow through a wire?

Answer 1

a magnetic field is produced around the wire

this can be increased by coiling the wire around a soft iron core

e.g. electromagnets are used on cranes for lifting iron

Question 2

What is the motor effect?

Answer 2

a motor can be made using a coil of wire that is free to rotate between two opposite magnetic poles

the size of the force is greatest when the wire is perpendicular to the the magnetic field

Question 3

How can the motor effect be increased?

Answer 3

increasing the strength of the magnetic field

increasing the size of the current

Question 4

What happens if the conductor is parallel to the magnetic field?

Answer 4

it will not experience a force

Question 5

What happens to the direction of the force is the magnetic field is reversed?

Answer 5

the force will be reversed

Question 6

How can the direction of the force be worked out

Answer 6

using Fleming’s left hand rule

point your forefinger in the direction of the magnetic field, north to south

point your second finger in the direction of the electric current, positive to negative

your thumb will point in the direction of movement