If the Young's modulus of a material is $2.4$ times its modulus of rigidity,what is the Poisson's ratio of the material?

If the volume of a wire remains unchanged when it is stretched,what is the Poisson's ratio for the wire?

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

$A$ 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:

A compressive force is applied to a uniform rod of rectangular cross-section so that its length decreases by $1 \%$. If the Poisson's ratio for the material of the rod is $0.2,$ which of the following statements is correct? "The volume approximately ..........."

$A$ cylindrical wire of radius $1\, mm$,length $1\, m$,Young's modulus $Y = 2 \times 10^{11}\, N/m^2$,and Poisson's ratio $\mu = \pi / 10$ is stretched by a force of $100\, N$. What will be its new radius (in $, mm$)?