Final answer:
The purpose of a microphone in a telephone is to convert sound energy into an analog electrical signal for transmission over telephone wires.
Step-by-step explanation:
In a telephone, the purpose of the microphone is to convert sound energy into an analog electrical signal, which can then be transmitted over the bridge tip and ring wires of a loop-line for immediate start. Microphones are devices that pick up acoustic sounds, such as someone's voice, and convert them into electrical signals that can be processed electronically. This conversion is an essential function in telecommunication as it allows voices to be transmitted over telephone lines. For instance, when a person speaks into a telephone microphone, the diaphragm within the microphone vibrates in response to the sound waves. This vibration generates an electrical signal that mirrors the pattern of the sound waves. This analog signal can be viewed using an oscilloscope, or further processed for transmission in a variety of mediums including radio waves in cell phones or as binary data for digital communication.