The force required to stretch a steel wire of $1\,cm^2$ cross-section to $1.1$ times its original length is $(Y = 2 \times 10^{11}\,N/m^2)$.

The mean distance between the atoms of iron is $3 \times 10^{-10} \ m$ and the interatomic force constant for iron is $7 \ N/m$. The Young's modulus of elasticity for iron is:

$A$ wire of length $L$ and radius $r$ is rigidly fixed at one end. On stretching the other end of the wire with a force $F$,the increase in its length is $l$. If another wire of same material but of length $2L$ and radius $2r$ is stretched with a force of $2F$,the increase in its length will be

The ratio of Young's modulus of the material of two wires is $2 : 3.$ If the same stress is applied on both,then the ratio of elastic energy per unit volume will be

The value of Young's modulus for a perfectly rigid body is ...........

$A$ metallic bar of Young's modulus $0.5 \times 10^{11} \,N \,m^{-2}$, coefficient of linear thermal expansion $10^{-5} \,^{\circ}C^{-1}$, length $1 \,m$, and area of cross-section $10^{-3} \,m^2$ is heated from $0^{\circ}C$ to $100^{\circ}C$ without expansion or bending. The compressive force developed in it is: