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Two children are at opposite ends of an aluminum rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the sound wave in air and in aluminum to reach the second child.
Velocity of sound in air v1 = 346 ms–1
Velocity of sound in aluminum v2 = 6420 ms–1
Let the length of the aluminum pipe = x m.
∴ Time = distance/velocity
Time taken in the air = xm / 346ms-1
Time taken in the air = x / 346s
Time taken in aluminum = xm / 6420ms-1
Time taken in aluminum = x / 6420s
Required ratio = x / 346s ÷ x / 6420s
⇒ x/346 x 6420/x
= 18.55