A wire of length L,area of cross section A is hanging from a fixed support. The length of the wire changes to `L_1` when mass `M` is suspended from its free end. The expression for Young's modulus is:

Options

A. `(Mg(L_(1)-L))/(AL)`
B. `(MgL)/(AL_(1))`
C. `(MgL)/(A(L_(1)-L))`
D. `(MgL_(1))/(AL)`

Answer

C

Explanation

Stress `=(Mg)/(A)`
Strain `=(Delta L)/(L) = (L_(1)- L)/(L)`
Young's modulus `=("Stress")/(Strain") = (MgL)/(A(L_(1)-L))`