Two rods of same material and volume having circular cross-section are subjected to tension $T$. Within the elastic limit,the same force is applied to both the rods. If the diameter of the first rod is half of the second rod,then the ratio of the extension of the first rod to the second rod will be: (in $: 1$)

Write the equation of bending in a rod. Write the unit of bending and its dimensional formula.

The pressure to be applied to the ends of a steel cylinder to keep its length constant upon raising its temperature by $100^{\circ} C$ is (thermal expansion coefficient, $\alpha = 11 \times 10^{-6} / K$, Young's modulus $Y = 200 \text{ GPa}$)

With a rise in temperature,the Young's modulus of elasticity

$A$ load of mass $M \ kg$ is suspended from a steel wire of length $2 \ m$ and radius $1.0 \ mm$ in Searle's apparatus experiment. The increase in length produced in the wire is $4.0 \ mm$. Now,the load is fully immersed in a liquid of relative density $2$. The relative density of the material of the load is $8$. The new value of increase in length of the steel wire is ........ $mm$.

$A$ metallic ring of radius $r$ and cross-sectional area $A$ is fitted into a wooden circular disc of radius $R$ $(R > r)$. If the Young's modulus of the material of the ring is $Y$, the force with which the metal ring expands is