The cross-sectional area of all wires is $10^{-4} \ m^2$. What is the displacement of point $D$?

Young's modulus of elasticity of a material depends upon

$A$ 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 ..... $mm$ $(Y = 2 \times 10^{11} \, N/m^2, g = 10 \, m/s^2)$.

The force required to stretch a steel wire of area of cross-section $1 \,mm^2$ to double its length is (Young's modulus of steel $= 2 \times 10^{11} \,N \,m^{-2}$)

The length of a metal wire is $L$, when it is subjected to tension $T$. If the tension is increased to $T+\Delta T$, the length becomes $L+\Delta L$. The natural length of the wire is

$A$ brass rod of length $2\,m$ and cross-sectional area $2.0\,cm^2$ is attached end to end to a steel rod of length $L$ and cross-sectional area $1.0\,cm^2$. The compound rod is subjected to equal and opposite pulls of magnitude $5 \times 10^4\,N$ at its ends. If the elongations of the two rods are equal,then the length of the steel rod $(L)$ is ........... $m$ $(Y_{Brass}=1.0\times 10^{11}\,N/m^2$ and $Y_{Steel} = 2.0 \times 10^{11}\,N/m^2)$.