ELECTROMAGNETIC INDUCTION

4 marks · Normal

A straight wire is moved quickly at right angles through the magnetic field between the poles of two magnets, as shown below.

A wire AB moving at right angles across a uniform magnetic field between north and south poles.

(a)

State the name of the process by which a voltage is produced in the wire.

[1 mark]

(b)

Explain how the movement of the wire causes a voltage to be induced in it.

[2 marks]

(c)

Give one way, other than moving the wire faster, to increase the size of the induced voltage.

[1 mark]

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show answer

(a) Electromagnetic induction

(b) — · must show Wire cuts through magnetic field lines (or field lines are cut), This induces a voltage (potential difference) in the wire

Show mark scheme and worked solution

Marking points

B1 (a) · 1 mark · State 'electromagnetic induction' correctly

B1 (b) · 1 mark · Explain that the wire cuts through magnetic field lines (or field lines cut the wire)

B1 (b) · 1 mark · State that this induces a voltage (potential difference)

B1 (c) · 1 mark · Give one correct way to increase voltage: stronger magnet or coil of wire (more turns)

Worked solution

a) The process is called electromagnetic induction.

b) Moving the wire at right angles through the magnetic field causes it to cut through the field lines. This action induces a voltage in the wire because the moving conductor cuts through magnetic field lines.

c) Using a stronger magnet increases the magnetic field, or using more turns of wire increases induced voltage.