$A$ steel wire of $1 \, m$ long and $1 \, mm^2$ cross-sectional area is hung from a rigid support. When a weight of $1 \, kg$ is hung from it,the change in length will be given by ..... $mm$ $(Y = 2 \times 10^{11} \, N/m^2, g = 10 \, m/s^2)$.

Two wires of same length having radius of $2 \ mm$ and $1.5 \ mm$ respectively are loaded with same weights. Extension of the second wire is double than that of the first wire. What is the ratio of the Young's modulus of the first wire to that of the second wire?

Young's modulus of elasticity of a material depends upon

There are two wires of the same material and same length. If the diameter of the second wire is two times the diameter of the first wire,then the ratio of the extension produced in the wires by applying the same load will be:

Evaluate the following statements:
$(a)$ Young's modulus of a rigid body is .....
$(b)$ $A$ wire increases by $10^{-6}$ times its original length when a stress of $10^8 \ N/m^2$ is applied to it. Calculate its Young's modulus.
$(c)$ The value of Poisson's ratio for steel is ......

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