ICSE Class 9 Answered
The sound of an explosion on the surface of the lake is heard by the man 120 m away and a diver 120 m below the point of explosion (i) explain who will hear the sound of explosion first and why ? (ii) if sound takes 2 s to reach the man, how much time will it take to reach the diver ?
Asked by nisha_vini29 | 18 Mar, 2016, 08:03: AM
Expert Answer
(i) The diver will hear the sound first.
The medium of propagation of sound for the man is through air and for the diver is through water. However, the speed of sound in water is greater than the speed of sound in air.
(ii) Time taken for the sound to reach the diver in water is given as
Time = Distance / Speed
Speed of sound in water = 1480 m/s
→Time = 120 m / 1480 m/s
Time = 0.081 s
Answered by Yashvanti Jain | 18 Mar, 2016, 06:20: PM
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