A moving-coil microphone contains a thin diaphragm attached to a coil of wire. The coil sits in the magnetic field of a permanent magnet.
Explain how the microphone converts a sound wave into a varying current.
A person speaks into the microphone more loudly, at the same pitch.
Describe how the current produced by the microphone changes.
A microphone and a loudspeaker contain similar parts.
Explain why a loudspeaker is said to do the reverse of a microphone.
48 exam-style questions on OCR GCSE Physics 4.2 Uses of magnetism, covering 4.2.1 The motor effect, 4.2.2 Fleming's left-hand rule, 4.2.3 The force on a current-carrying conductor, 4.2.4 The electric motor, 4.2.5 Electromagnetic induction, 4.2.6 Alternators and dynamos, 4.2.7 How transformers work, 4.2.8 Transformer turns ratio, 4.2.9 Potential differences and turns in transformers, and 4.2.10 Microphones, loudspeakers and headphones. Each one has a worked solution and a mark scheme showing where the marks go.