An aluminium rod with Young's modulus $Y =7.0$ $\times 10^{10} N / m ^2$ undergoes elastic strain of $0.04 \%$. The energy per unit volume stored in the rod in SI unit is:
$5600$
$8400$
$2800$
$11200$
A wire fixed at the upper end stretches by length $l$ by applying a force $F$. The work done in stretching is
When a block of mass $M$ is suspended by a long wire of length $L$, the length of the wire become $(L+l) .$ The elastic potential energy stoped in the extended wire is :
On stretching a wire, the elastic energy stored 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 $\left.J / m ^3\right]$
If the force constant of a wire is $K,$ the work done in increasing the length of the wire by $l$ is