If refractive index of a prism is \(\mathrm{cot(A/2)}\), then the minimum angle of deviation is:
1. \(180^{\circ}-A\)
2. \(180^{\circ}-2A\)
3. \(90^{\circ}-A\)
4. \((A/2)\)

The refractive index of the material of a prism is $\sqrt{2}$ and its refracting angle is \(30^{\circ}\). One of the refracting surfaces of the prism is made a mirror inwards. A beam of monochromatic light entering the prism from the other face will retrace its path after reflection from the mirrored surface if its angle of incidence on the prism is: