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14. waves and sound — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysics14. waves and sound1 Mark
MCQ
A man stands in front of a hillock and fires a gun. He hears an echo after $1.5\, sec$. The distance of the hillock from the man is ...... $m$ (velocity of sound in air is $330\, m/s$)
  • A
    $220$
  • ✓
    $247.5 $
  • C
    $268.5$
  • D
    $292.5$
✓

Answer

Correct option: B.
$247.5 $
b
(b) If $d$ is the distance between man and reflecting surface of sound then for hearing echo

$2d = v \times t \Rightarrow d = \frac{{330 \times 1.5}}{2} = 247.5\,m$

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