Question

A steel wire is suspended vertically from a rigid support. When loaded with a weight in air, it expands by and when the weight is immersed completely in water, the extension is reduced to `L_(w)`. Then relative done of the material of weight is
A. `(L_(a))/(L_(a) - L_(w))`
B. `(L_(w))/(L_(a))`
C. `(L_(a))/(L_(w))`
D. `(L_(w))/(L_(a) - L_(w))`

Answer 1

Correct Answer - A

`L_(a) = (WL)/(YA), L_(w)=([W-(W)/(rho_(o))rhow]L)/(YA)=W[1-(rho_(w))/(rho_(0))]L`
`(L_(a))/(L_(w))=[1-(rho_(w))/(rho_(o))]rArr(rho_(o))/(rho_(w))=(L_(a))/(L_(a)-L_(w))`