MCQ
The echo of a gun shot is heard $8\, sec$. after the gun is fired. How far from him is the surface that reflects the sound .... $m$ (velocity of sound in air $= 350 \,m/s$)
- ✓$1400$
- B$2800$
- C$700 $
- D$350 $
✓
Answer
Correct option: A.
$1400$
a
(a) Suppose the distance between shooter and reflecting surface is $d$.
(a) Suppose the distance between shooter and reflecting surface is $d$.
Hence time interval for hearing echo is
$t = \frac{{2d}}{v}$ ==> $8 = \frac{{2d}}{{350}}$ ==> $d = 1400\,m$.
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