If $x$ longitudinal strain is produced in a wire of Young's modulus $y,$ then energy stored in the material of the wire per unit volume is

The strain energy stored in a body of volume $V$ due to shear strain $\phi$ is (shear modulus is $\eta$ )

The elastic potential energy stored in a steel wire of length $20\,m$ stretched through $2 \,m$ is $80\,J$. The cross sectional area of the wire is $………\,mm ^2$ (Given, $y =2.0 \times 10^{11}\,Nm ^{-2}$ )

The work done in increasing the length of a $1$ $metre$ long wire of cross-section area $1\, mm^2$ through $1\, mm$ will be ……. $J$ $(Y = 2\times10^{11}\, Nm^{-2})$

A metallic rod of length $I$ and cross-sectional area $A$ is made of a material of Young's modulus $Y$. If the rod is elongated by an amount $y$, then the work done is proportional to ……