A moving-coil microphone is connected to an amplifier and a loudspeaker. A student pushes the microphone diaphragm slowly inwards, holds it still, and then releases it so it returns rapidly. The amplifier does not distort the signal.
Which description of the microphone signal is correct?
A pulse, then the same voltage, then an opposite pulse with a smaller peak magnitude.
A pulse, then zero, then a same-polarity pulse with a greater peak magnitude.
A pulse, then zero, then an opposite pulse with a greater peak magnitude.
A pulse, then the same voltage, then a same-polarity pulse with a smaller peak magnitude.
92 exam-style questions on Edexcel GCSE Physics 13.1 Inducing a current, covering 13.1.1 Producing an electric current by induction, 13.1.2 Factors affecting the induced potential difference, 13.1.3 Alternators and dynamos, and 13.1.4 Microphones and loudspeakers. Each one has a worked solution and a mark scheme showing where the marks go.