Answer:
A) a coil separated from a magnet by a dielectric
B) a membrane
Explanation:
When sound waves enter the microphone, they meet the diaphragm, which is a membrane that moves back and forth when sound waves hit it. This vibration is converted into an electrical signal by the microphone.
The coil is attached to the diaphragm, so when the diaphragm starts vibrating, so does the coil.
As the coil vibrates, it moves back and forth between a magnet. Movement between the magnetically charged coil and the magnet creates electrical energy in the signal.
The magnet creates a magnetic field for the coil so that vibrations can create an electrical signal.
