On a clear summer evening the speed of sound in air is measured to be 346ms−1 at 25∘C. A boy standing on level ground claps his hands once and waits for an echo from a tall wall directly in front of him.
(a) Calculate the minimum distance of the wall from the boy so that he can hear a distinct echo.
(b) The temperature rises uniformly to 35∘C, for which the speed of sound increases by 0.6ms−1 per degree Celsius rise. Determine again the minimum distance required under the new conditions.