question_answer 51)

  A girl is sitting in the middle of a park of dimension 12m x 12m. On the left side of it there is a building adjoining the park and on 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 the echo of this sound? Explain your answer.

Answer:

  No, it is not possible (or the girl to hear the echo of this sound, because the distance between girl and obstacle (building) is only 6m approx but echo is heard only if the minimum distance between the observer at the source of sound and the obstacle is 11.3 m.