If one end of a wire is fixed with a rigid support and the other end is stretched by a force of $10 \,N,$ then the increase in length is $0.5\, mm$. The ratio of the energy of the wire and the work done in displacing it through $1.5\, mm$ by the weight is

Does the energy stored in a spring changes when it stretched or compressed ?

A wire fixed at the upper end stretches by length $l$ by applying a force $F$. The work done in stretching is

The work done in stretching an elastic wire per unit volume is 

A metal wire having Poisson's ratio $1 / 4$ and Young's modulus $8 \times 10^{10} \,N / m ^2$ is stretched by a force, which produces a lateral strain of $0.02 \%$ in it. The elastic potential energy stored per unit volume in wire is [in $\left.J / m ^3\right]$

Two wires of the same material (Young's modulus  $Y$ ) and same length $L$  but radii  $R$  and  $2R$  respectively are joined end to end and a weight  $W$  is suspended from the combination as shown in the figure. The elastic potential energy in the system is