Question

Give reasons to why one cannot hear the sound produced by other sources on the moon?
A. No presence of a medium for propagation.
B. the radiations from the sun destroy all the sound waves created.
C. sound only propagates on the earth.
D. none of these.

Answer 1

Hint: We already have studied that the sound waves require a medium for their propagation. Sound waves cannot travel in the airless area or somewhere where there is the absence of a medium, but it requires molecules of a medium, for example, air to travel by the process of compression and rarefaction.


Complete step by step answer:
We all know that sound wave is a mechanical wave, and it has travelled through a medium to get it to the other end. As we have seen that the gravity of the earth is responsible for holding the atmosphere with earth, so, due to the presence of air in the earth, the sound travels efficiently while on the moon there is not enough gravity to keep the atmosphere. When radiation of the sunlight strikes on the moon, the lunar gases present there gain energy from the sunlight and the molecules of the gases are so much excited that the velocity of the gas molecules become more than the escape velocity.
Since the surface of the moon has no possible atmosphere and hence it has no medium, so, therefore, the sound waves find no medium to travel and sound can’t be heard on the moon.
Therefore, the correct option is A that the absence of medium to propagate, the sound is not heard on the moon.


Note: Speed of sound is different in a different medium. Speed of sound is having an inverse relation with density. As during the rainy season, the density of air increases and hence the speed of sound during the rainy season increases.