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प्रश्न
The speed of sound in air is about 330 ms-1. Express this speed in kmh-1. How long will the sound take to travel 99 km?
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उत्तर
Speed of sound in air = 330 m/sec
∴ Speed in km/h = `(330xx60xx60)/1000`
= 1188 km/h
Time taken by sound to cover 99 km
= `99/1188=1/12` hours
= `1/12xx60` = 5 minutes
or 5 × 60 = 300 seconds
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