Figure shows the strain-stress curve for a given material. What are $(a)$ Young’s modulus and $(b)$ approximate yield strength for this material?

A $0.1 \mathrm{~kg}$ mass is suspended from a wire of negligible mass. The length of the wire is $1 \mathrm{~m}$ and its crosssectional area is $4.9 \times 10^{-7} \mathrm{~m}^2$. If the mass is pulled a little in the vertically downward direction and released, it performs simple harmonic motion of angular frequency $140 \ \mathrm{rad} \mathrm{s}^{-1}$. If the Young's modulus of the material of the wire is $\mathrm{n} \times 10^9 \mathrm{Nm}^{-2}$, the value of $\mathrm{n}$ is

In which case there is maximum extension in the wire, if same force is applied on each wire

A copper wire of length $2.2 \;m$ and a steel wire of length $1.6\; m ,$ both of diameter $3.0 \;mm ,$ are connected end to end. When stretched by a load, the net elongation is found to be $0.70 \;mm$. Obtain the load applied in $N$.

A uniform heavy rod of mass $20\,kg$. Cross sectional area $0.4\,m ^{2}$ and length $20\,m$ is hanging from a fixed support. Neglecting the lateral contraction, the elongation in the rod due to its own weight is $x \times 10^{-9} m$. The value of $x$ is

(Given. Young's modulus $Y =2 \times 10^{11} Nm ^{-2}$ અને $\left.g=10\, ms ^{-2}\right)$