The length of a rod under longitudinal tension $T_1$ is $L_1$ and that under longitudinal tension $T_2$ is $L_2$. What is the actual length of the rod,in the absence of tensions?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Steel is used in the construction of buildings and bridges.
Reason $R$: Steel is more elastic and its elastic limit is high.
In the light of the above statements,choose the most appropriate answer from the options given below:

The elastic limit of a metal is $\frac{400}{\pi} \text{ MPa}$. If a rod of this metal is to support a $484 \text{ N}$ load without exceeding its elastic limit, the minimum diameter of the rod is: (in $\text{ mm}$)

$A$ and $B$ are two wires. The radius of $A$ is twice that of $B$. They are stretched by the same load. Then the stress on $B$ is

Two wires $A$ and $B$ are stretched by the same load. The radius of wire $A$ is double the radius of wire $B$. The stress on the wire $B$ as compared to the stress on the wire $A$ is

The increase in length is $l$ of a wire of length $L$ by the longitudinal stress. Then the stress is proportional to