Q. If man were standing unsymmetrical between parallel cliffs, claps his hands and starts hearing a series of echoes at a intervals of 1 s. If speed of sound in air is $340ms^{- 1}$ , the distance between two cliffs would be
A) 340m
B) 510m
C) 170m
D) 680m
Explanation
(b) Let $x$ be distance of person from one cliff and $y$ be distance of person from 2nd cliff. Let $y > x.$
$\therefore x + x = v \times t_{1} = 340 \times 1 = 340$
$x = 170\ m$
$y + y = v \times t_{2} = 340 \times 2 = 680$
$y = 340\ m$.
Distance between two cliffs
$= x + y = 170 + 340 = 510m$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.