Microphones (ht Only) (GCSE Physics)

When using a dynamic microphone as a pickup for a musical instrument string (e.g., acoustic guitar), why is placement crucial?

A microphone’s output cable picks up a time-varying magnetic field from a nearby loudspeaker transformer, producing hum. Which engineering solution targets the problem most directly?

Lenz’s law gives the sign in Faraday’s law. What physical statement best describes Lenz’s law?

A microphone coil moves in a magnetic field and experiences a back emf when the circuit is closed. How does back emf affect the coil motion and microphone output?

A moving-coil microphone is placed near the pole face of the magnet with the coil axis perpendicular to the field. For maximum induced emf the coil should:

In a moving-coil (dynamic) microphone the sound causes the coil to move in a magnetic field and an electrical signal is produced by electromagnetic induction. Which equation gives the instantaneous emf induced across a straight wire of length l moving at speed v at right angles to a magnetic field of strength B?

A moving-coil microphone has a coil of many turns attached to the diaphragm. Which change would increase the amplitude of the voltage produced for a given sound pressure?

A moving-coil microphone shows nonlinearity at very high sound pressure levels. Which physical cause is most likely?

A dynamic microphone converts mechanical power from sound into electrical power. Which statement about energy conversion is correct?

A moving-coil microphone’s output leads must be connected to the preamplifier with correct polarity. If one mic sounds thin when added in parallel with another and cancels at some frequencies, what is the likely cause?

Which property of a moving-coil microphone most affects its transient (attack) response to sharp sounds?