Q142 / 200 · Manipal (MET) 2012 · Physics

A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is $340 \mathrm{~ms}^{-1}$, the distance between the cliffs is

  • A
    680 m
  • B
    1700 m
  • Correct answer
    C
    340 m
  • D
    1620 m

Solution

Let the distance between the two cliffs be $d$. Since, the man is standing midway between the two cliffs, then the distance of man from either end is $d / 2$. The distance travelled by sound (in producing an echo) $2 \times \frac{d}{2}=v \times t \Rightarrow d=340 \times 1=340 \mathrm{~m}$

Hence, the correct answer is option: 'C'.

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