For the tangential stress on the cross-section $PQRS$ to be maximum,$\theta = $ ....... $^o$

The load versus elongation graph for four wires of the same material is shown in the figure. The thinnest wire is represented by the line

Below are two statements. One is labeled as Assertion $(A)$ and the other as Reason $(R).$
Assertion $(A):$ The property of an object that allows it to regain its original shape after the external force applied to it is removed is called elasticity.
Reason $(R):$ The restoring force depends on the intermolecular and interatomic forces in a solid.
In the context of the above statements,choose the most appropriate answer from the options given below:

If the temperature increases,the modulus of elasticity

$A$ lift of mass $1600 \text{ kg}$ is supported by a thick iron wire. If the maximum stress which the wire can withstand is $4 \times 10^8 \text{ N/m}^2$ and its radius is $4 \text{ mm}$, then the maximum acceleration the lift can take is . . . . . . $\text{m/s}^2$. (Take $g = 10 \text{ m/s}^2$ and $\pi = 3.14$)

Is it possible to double the length of a metallic wire by applying force over it?