Question

The audio signal

• A. can be sent directly over the air for large distance
• B. can not be sent directly over the air for large distance
• C. possesses very low frequency
• D. possesses very high frequency

Answer 1

The correct option is D possesses very high frequency

The energy of a wave is directly proportional to its frequency. At audio frequencies (20 Hz to 20 kHz), the signal power is very small.
The high frequency signals can be sent thousands of miles even with comparatively small power. Therefore, if audio signal is to be transmitted properly, some means must be devised which will permit transmission to occur at high frequencies while it simultaneously allows the carrying of audio signal.