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प्रश्न
An observer stands at a distance of 850 m from a cliff and fires a gun. After what time gap will he hear the echo? If sound travels at a speed of 350 m/sec., in air.
उत्तर
Given: d = 850 metre, t = ?, speed v = 350 m/s
∴ t = `"2d"/"v"`
⇒ t = `(2xx850)/350`
⇒ t = `(2xx17)/7`
= 4.86 sec.
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