PH-1613
Electromagnetic induction
Physics · Secondary 4 · Hard · Electromagnetic induction
A small generator consists of a coil rotating in a magnetic field. When the coil is turned faster, the lamp connected to it glows more brightly. Using Faraday’s law of electromagnetic induction, explain why the lamp becomes brighter when the coil spins faster.
- The faster rotation increases the rate of change of magnetic flux, so a larger e.m.f. and current are induced.
- The faster rotation increases the coil’s resistance, so more power is produced.
- The faster rotation reduces the magnetic field strength, so less energy is lost.
- The faster rotation cools the lamp filament, so it can carry more current.
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