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 $\left.J / m ^3\right]$
$2.56 \times 10^4$
$1.78 \times 10^6$
$3.72 \times 10^2$
$2.18 \times 10^5$
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
A uniform wire of length $L$ and radius $r$ is twisted by an angle $\alpha$. If modulus of rigidity of the wire is $\eta$, then the elastic potential energy stored in wire, is .........
Why do spring balances show wrong readings of weight after they have been used for a long time ?
$K$ is the force constant of a spring. The work done in increasing its extension from ${l_1}$ to ${l_2}$ will be
Two steel wires having same length are suspended from a ceiling under the same load. If the ratio of their energy stored per unit volume is $1: 4,$ the ratio of their diameters is