ELECTROMAGNETIC INDUCTION
3 marks · NormalWhen a magnet is pushed into a coil of wire, a voltage is produced across the ends of the coil. The voltage disappears if the magnet stops moving.
Explain why a voltage is only induced when the magnet is moving.
Give one way to increase the maximum voltage produced in this experiment.
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.
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(a) — · must show Induction requires movement, Movement causes field lines to be cut (or cutting action between magnet and coil)
(b) Move the magnet faster, use a stronger magnet, or increase the number of turns in the coil.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States that relative movement is required
B1 (a) · 1 mark · Links movement to cutting field lines (or similar)
B1 (b) · 1 mark · States a correct way to increase voltage
Worked solution
a) A voltage is only induced when the magnet is moving, because then the magnetic field lines are being cut by the coil (or vice versa). If there is no movement, there is no cutting and therefore no induced voltage.
b) Move the magnet faster, use a stronger magnet, or increase the number of turns in the coil.