passwella.
Menu

JAMB Physics 1980 Question 45

Question 45

Sound

A man stands one-third of the way between two walls and claps his hands. He hears two distinct echoes 1 s apart. If the speed of sound is 330 m s−1 the distance between the walls is

  1. A.33 m
  2. B.110 m
  3. C.220 m
  4. D.330 m
  5. E.495 m
Show the answer and explanation

Answer: E (495 m)

Explanation

If the walls are x apart, the echoes travel 2x/3 and 4x/3, a difference of 2x/3. Then 2x/3 = 330 × 1, so x = 495 m.