(a) What is meant by intensity of sound ?
(b) Mention the conditions for an echo to be heard clearly.
© A ball is dropped into a pond from a height of 44.1 m. The splash of sound is heard 3.13 second after the ball is dropped. Determine the velocity of sound in air.
(a) What is meant by intensity of sound ? (b) Mention the conditions for an echo to be heard clearly
(a) The amount of sound energy passing each second through unit area.
(b) (i) Time interval between the original sound and the reflected sound must be 0.1 s.
(ii) The minimum distance of obstacle from the source sound must be 17 m.
© Given, h = 44.1 m,
u = 0,
g = 9.8 m s^-2
Using the equation S = ut + 1/2 at^2, we have
t^2 = (44.1x2) /9.8 = 44.1 / 4.9 = 9
or t = 3 second
Time taken by sound to reach height = 3.13 - 3 = 0.13 s
Hence, V = d/t = 44.1/0.13 = 339.2 ms^-1