Correct Answer - 0.005 rad

Refer to

for equilibrium position of mass M, `Mg = 2T sin theta…… (i)`

if `theta` is small, sin `theta ~~ theta = x//L….. (ii)`

`As, T = (YA)/(L) Delta L = (YA)/(L)[(L^2 + x^2)^(1//2)-L]`

From (i) `Mg = (2YA x^2)/(2L^2) xx sin theta = YA theta^2 xx theta = YA theta^3`

or `theta = ((Mg)/(YA))^(1//3) = [(1xx10)/(2xx 10^(11)xx4 xx10^(-4))]^(1//3)`

`~~ 0.005 rad`