Question

A girl is sitting in the middle of a park of dimensions 15 m x 10 m. On the left side of the park, there is a building adjoining the park and on the right side of the park, there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear echo of this sound? Explain.

Explain with proper justifications.

Points : 10 ☺

Answer 1

speed of sound in air = 340 m/s
minimum time required to hear echo =0.1s

distance
= 340 x 0.1/ 2
= 17 m

therefore
the reflector should be at a distance of 17 m for the echo to be heard

the length of the park is 15 m and the breadth is 10 m
the building is located 15 m or 10 m away from the source is the sound

in both the cases the distance between the source and the reflector is less than 17 m

so , echo Will not be heard by the girl

Answer 2

echo sound is concept of multiple reflection of sound .
a sound is produced on the road by cracker . sound moves and strike the wall and then reflected . opposite directionof initial motin of sound or some sound distroy another direction .
reflecting sound heared by girl .
this is not matter what is the frequency of resultant sound . but girl hear sound . this is true .