A $5\, m$ long aluminium wire ($Y = 7 \times {10^{10}}N/{m^2})$ of diameter $3\, mm$ supports a $40\, kg$ mass. In order to have the same elongation in a copper wire $(Y = 12 \times {10^{10}}N/{m^2})$ of the same length under the same weight, the diameter should now be, in $mm.$

A force of $200\, N$ is applied at one end of a wire of length $2\, m$ and having area of cross-section ${10^{ - 2}}\,c{m^2}$. The other end of the wire is rigidly fixed. If coefficient of linear expansion of the wire $\alpha = 8 \times 10{^{-6}}°C^{-1}$ and Young's modulus $Y = 2.2 \times {10^{11}}\,N/{m^2}$ and its temperature is increased by $5°C$, then the increase in the tension of the wire will be ........ $N$

A rubber pipe of density $1.5 \times {10^3}\,N/{m^2}$ and Young's modulus $5 \times {10^6}\,N/{m^2}$ is suspended from the roof. The length of the pipe is $8 \,m$. What will be the change in length due to its own weight

The dimensions of four wires of the same material are given below. In which wire the increase in length will be maximum when the same tension is applied

If the ratio of lengths, radii and Young's moduli of steel and brass wires in the figure are $a, b$ and $c$ respectively, then the corresponding ratio of increase in their lengths is

The Young's modulus of a wire of length $L$ and radius $r$ is $Y$. If the length is reduced to $\frac{L}{2}$ and radius is $\frac{r}{2}$ , then the Young's modulus will be