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

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

Wires $A$ and $B$ are made from the same material. $A$ has twice the diameter and three times the length of $B.$ If the elastic limits are not reached, when each is stretched by the same tension, the ratio of energy stored in $A$ to that in $B$ is

When a $4\, kg$ mass is hung vertically on a light spring that obeys Hooke's law, the spring stretches by $2\, cms$. The work required to be done by an external agent in stretching this spring by $5\, cms$ will be ……… $joule$       $(g = 9.8\,metres/se{c^2})$

A wire is suspended by one end. At the other end a weight equivalent to $20\, N$ force is applied. If the increase in length is $1.0\, mm$, the increase in energy of the wire will be …….  $joule$