Two children are at opposite ends of an aluminium rod. One strikes the end of rod with a stone. Find the ratio of times taken by sound wave in air and in aluminium to reach the second child (Given: Speed of sound in air = 346 m/s; Speed of sound in aluminium = 6240 m/s)


Let, the length of aluminium rod is l.

Now, firstly we calculate the speed of sound in air.


We know that,


Speed of sound (in air) =


346 =


Time taken in air = (i)


Now, speed of sound in aluminium.


We know that,


Speed of sound (in aluminium) =


6420 =


Time taken in aluminium = (ii)


Now by dividing (i) and (ii), we get:



= 6420/346


=


Therefore, the ratio is 18.55:1


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