When a block of mass $M$ is suspended by a long wire of length $L$,the length of the wire becomes $(L+l)$. The elastic potential energy stored in the extended wire is:

The elastic energy stored in a wire of Young's modulus $Y$ is

An elastic material of Young's modulus $Y$ is subjected to a stress $S$. The elastic energy stored per unit volume of the material is

Two wires $A$ and $B$ having same length and material are stretched by the same force. Their diameters are in the ratio $1: 3$. The ratio of energy density of wire $A$ to that of wire $B$ when stretched,is (in $: 1$)

What is called elastic energy density? Write its formula and dimensional formula.

If the work done in stretching a wire by $1 \ mm$ is $2 \ J$,the work necessary for stretching another wire of the same material but with double the radius of cross-section and half the length by $1 \ mm$ is: