ELECTROMAGNETIC INDUCTION
2 marks · EasyA dynamo is attached to a bicycle wheel. Describe briefly what happens to the magnetic field inside the dynamo as the bicycle wheel turns.
Explain how the turning magnet inside the dynamo leads to a current in the coil.
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(a) The magnetic field inside the dynamo rotates as the magnet turns.
(b) The rotating field causes the field lines to cut through the coil, inducing a current by electromagnetic induction.
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Marking points
B1 (a) · 1 mark · Correctly states that the magnetic field rotates as the magnet turns.
B1 (b) · 1 mark · Explains that the rotating magnetic field cuts the coil, causing electromagnetic induction.
Worked solution
(a) As the magnet turns, the magnetic field also turns (rotates) inside the dynamo.
(b) The rotating magnetic field causes field lines to cut through the coil, which induces a current in the coil (electromagnetic induction).