What is the modulus of rigidity of a liquid?

When a spiral spring is stretched by suspending a load from it,the strain produced is called . . . . . . strain.

The strain energy stored in a body of volume $V$ due to shear strain $\phi$ is (shear modulus is $\eta$ ).

The dimensions of shear modulus are

$A$ slab of side $50 \text{ cm}$ and thickness $10 \text{ cm}$ is subjected to a shearing force of $10^5 \text{ N}$ on its narrow edge. If the lower edge is riveted to the floor and the upper edge is displaced by $0.2 \text{ mm}$, then the shear modulus of the material of the slab is: (in $\text{ GPa}$)

Two wires $A$ and $B$ of same length and of same material have radii $r_1$ and $r_2$ respectively. Their one end is fixed with a rigid support and at the other end,an equal twisting couple is applied. Then,the ratio of the angle of twist at the end of $A$ to the angle of twist at the end of $B$ will be ..............