A boy stands x m away from a high wall and claps his hands at a steady rate so that each clap coincides with the echo of the one before. If he makes 60 claps in 2 minutes and the velocity of sound is 340 m/s , then the distance x from the wall is

Step-by-step solution

Time taken for 60 claps is 2 minutes = 120 s . Time interval between two consecutive claps is T = 120 60 = 2 s . Let the distance of the boy from the wall be x . The sound travels a distance of 2x (to the wall and back) to form an echo. Time taken for the echo to return is t = 2x v . Since each clap coincides with the echo of the previous one, the time for the echo to return equals the time interval between claps, so t = T . 2x 340 = 2 2x = 680 x = 340 m Answer: 340 m