The shear strain is possible in .............

Hooke's law is applicable for ....

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:

Why does strain have no unit?

If a solid breaks under a pressure greater than $13 \ atm$ and that solid has a specific gravity of $4$,what is the maximum height of a cylinder made from the solid that can be built at the Earth's surface (in $m$)? (Note: $1 \ atm = 10^5 \ Pa$ and take $g = 10 \ m/s^2$.)

$A$ force of $10 \,N$ is required to break a wire of radius $1 \,mm$. The force required to break the wire of the same material, but radius $3 \,mm$ will be