I have heard that speed of sound does not change with change in pressure so why according to formula v equals square root of pressure by density; v is directly proportional to square root of pressure?

1 Answer
Dec 5, 2017

I think the bottom line is that normally density changes when pressure does, and the speed of sound is related to density. Therefore what you have heard is not accurate (except in very special and unusual circumstances).

Explanation:

Density is the key issue: the speed of sound does change with the density of the air. It is possible that, for example, a change in the humidity of the air could mean there was no change in density (mass per unit volume) despite a change in pressure, so that a change in pressure would not lead to a change in the speed of sound. This would be rare, though.