CSS Screening Exams Quizzes MCQs Quizzes CSS Pre Screening GK of Everyday Science Test 5

Question:
The echo (reflected sound) will be distinctly heard only at ordinary temperatures if the distance of the reflecting surfaces from the source of sound is at least:

Option A):
100 ft
Option B):
56 ft
Option C):
120 ft
Option D):
1120 ft

Correct Answer is Option B):
56 ft