GCSE Standard Questions: The Motor Effect

Q4. The circle (with the cross in it) below represents a straight wire carrying a current. The cross shows that the current is into the plane of the paper.

(a) Complete the diagram to show the magnetic field pattern around the wire.

[2 marks]

(b) The magnetic flux density 10 cm from the wire is 4 microtesla.

Which of the following is the same as 4 microtesla?

Tick one selection.

Tick here
4 x 10-2 T
4 x 10-3 T
4 x 10-6 T
4 x 10-9 T


[1 mark]

(c) Here is a diagram of a simple electric motor.

When there is a current in the coil, the coil rotates continuously. Explain why.

[4 marks]

(Total 7 marks)