question_answer

  A girl is sitting in the middle of a park of  dimension 12m x 12 m. 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:

    For hearing distinct echoes, the minimum distance of obstacle from the source of sound must be 17.2 m. Since, distance of girl from sound source is less than 17.2 m. So, it is not possible for the girl to hear to echo of this sound.