ELECTROMAGNETIC INDUCTION
4 marks · NormalA portable generator is used at a roadworks site to provide electrical power. The generator has a coil rotating inside a strong magnetic field.
Describe how electricity is produced in this generator and state two factors that will increase the amount of electricity generated.
Describe what happens as the generator coil turns inside the magnetic field.
State two ways the amount of electricity generated can be increased.
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(a) — · must show Coil turns (or rotates) inside magnetic field, Field lines are cut by the coil, Voltage is induced in the coil (current if connected circuit)
(b) Increase speed of rotation; use a stronger magnet; increase number of turns in the coil (any two).
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Marking points
B1 (a) · 1 mark · Describes turning coil inside magnetic field
B1 (a) · 1 mark · States voltage induced due to cutting field lines (or current)
B1 (b) · 1 mark · First correct way to increase output
B1 (b) · 1 mark · Second correct way to increase output
Worked solution
a) As the coil turns inside the magnetic field, it cuts through magnetic field lines. This induces a voltage in the coil, and a current can flow if a circuit is present.
b) Increase the speed of rotation, use a stronger magnet, or increase the number of coil turns (any two).