Question

Suppose a stick is struck against a frying pan in vacuum, which of the following is/are true?
A. The frying pan vibrate
B. We are able to hear the sound
C. We can hear the sound just for few minutes
D. None of the above

Answer 1

Hint: To answer this question, we need to know the properties of sound. By knowing the characteristics of sound we will be able to answer the question. Sound is a longitudinal elastic wave unlike light which is an electromagnetic transverse wave. So it will have some difference in its behavior compared to light.

Complete step by step answer:
We know the origin of any kind of sound is vibration. When a body vibrates with a frequency in a specific range, we can hear its sound. Again sound is an elastic wave. An elastic wave needs some medium to propagate. While propagating through the medium, the particles of the medium vibrate parallel to the direction of propagation, that is why it is a longitudinal wave. Now when a stick is struck against a frying pan obviously the frying pan starts to vibrate so the option A will be true. Now as there is vacuum that is there is presence of any medium, the sound produced by the vibration of the frying pan will not be able to propagate. So nothing will come to our ear and we will not be able to hear any sound.

So, the correct answer is “Option A”.

Note: Sound needs a medium to propagate because it is a mechanical wave. The mechanical waves transmit energy and momentum through the limited motion of the particles of the material medium, while the medium remains unshifted. So if there is no material medium it cannot propagate. But this is not the case with light as it is an electro-magnetic wave.