The diagram below shows the change in the length $X$ of a thin uniform wire caused by the application of stress $F$ at two different temperatures $T_1$ and $T_2$. The variation shown suggests that

What are elastomers? Plot the stress $\to$ strain curve for them and explain.

$A$ student plots a graph from his readings on the determination of Young's modulus of a metal wire but forgets to label the axes. The quantities on $X$ and $Y$ axes may be respectively:

In plotting stress versus strain curves for two materials $P$ and $Q$,a student by mistake puts strain on the $y$-axis and stress on the $x$-axis as shown in the figure. Then the correct statement$(s)$ is(are):
$(A)$ $P$ has more tensile strength than $Q$
$(B)$ $P$ is more ductile than $Q$
$(C)$ $P$ is more brittle than $Q$
$(D)$ The Young's modulus of $P$ is more than that of $Q$

$A$ stress-strain graph for a metal is shown. The part in which Hooke's law holds good is

The graph shows the behavior of a length of wire in the region for which the substance obeys Hooke's law. $P$ and $Q$ represent: