A massless rod of length l is hung from the ceiling with the help of two identical wires attached at its ends. A block is hung on the case, the frequency of the `1^(st)` harmonic of the wire on the left end is equal to the frequency of the `2^(nd)` harmonic of the wire on the right. The value of X is

Options

A. `1//5`
B. `1//4`
C. `4l//5`
D. `3l//4`

Answer

5

Explanation

`v = sqrt((T)/(mu)) = sqrt((0.5)/(10^(-3)//0.2)) = 10 m//sec`.
`v = flambda`
`10 = (100)lambda rArr lambda = 0.1 m = 10 cm`
distance between two successive nodes `= (lambda)/(2) = 5 cm`