For a given material, the Young's modulus is $2.4$ times its modulus of rigidity. Its Poisson's ratio is ......

Which of the following relations is true?

$A$ tension of $20 \,N$ is applied to a copper wire of cross-sectional area $0.01 \,cm^2$. The Young's modulus of copper is $1.1 \times 10^{11} \,N/m^2$ and the Poisson's ratio is $0.32$. The decrease in the cross-sectional area of the wire is:

On all the six surfaces of a unit cube,an equal tensile force of $F$ is applied. The increase in length of each side will be ($Y =$ Young's modulus,$\sigma =$ Poisson's ratio).

The Young's modulus of the material of a wire is $6 \times 10^{12} \ N/m^2$ and there is no transverse strain in it,then its modulus of rigidity will be

$A$ copper wire of cross-sectional area $0.01 \ cm^2$ is under a tension of $22 \ N$. Find the percentage change in the cross-sectional area (Young's modulus of copper $= 1.1 \times 10^{11} \ N \ m^{-2}$ and Poisson ratio $= 0.32$).