GENERATORS
3 marks · EasyA hand-held generator is used to power a lamp for a camping tent.
Describe what happens inside the generator as you turn its handle.
Explain why turning the handle faster lights the lamp more brightly.
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) A coil (or a magnet) rotates inside a magnetic field, causing field lines to be cut.
(b) Turning the handle faster causes the coil (or magnet) to move more quickly, so more magnetic field lines are cut per second, inducing a bigger voltage and current, making the lamp brighter.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Mentions coil (or magnet) rotating in a magnetic field to cut field lines
B2 (b) · 1 mark · Explains that faster movement cuts more field lines per second (higher rate)
B3 (b) · 1 mark · Links higher induced voltage/current to brighter lamp
Worked solution
a) Turning the handle rotates a coil (or a magnet) inside a magnetic field, causing it to cut field lines.
b) Turning faster means more field lines are cut each second. This induces a bigger voltage and current, so the lamp shines more brightly.