At a prayer meeting, the disciples sing JAI-RAM JALRAM. The sound amplified by a loudspeaker comes back after reflection from a building at a distance of 80 m from the meeting. What maximum time interval can be kept between one JAI-RAM and the next JAI-RAM so that the echo does not disturb a listener sitting in the meeting. Speed of sound in air is 320ms−1.
Here given, s=80m×2=160m
v =320 m/s
So, the maximum time interval will be
t=sv=160320=0.5 seconds