A tall man, of height \(6\) feet, wants to see his full image. The required minimum length of the mirror will be:

1.	\(12\) feet	2.	\(3\) feet
3.	\(6\) feet	4.	Any length

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:
1. \(60^{\circ}\)
2. \(0^{\circ}\)
3. \(30^{\circ}\)
4. \(45^{\circ}\)

For the given incident ray as shown in the figure, in the condition of the total internal reflection of this ray, the minimum refractive index of the prism will be:

1. $\frac{\sqrt{3}+1}{2}$

2. $\frac{\sqrt{2}+1}{2}$

3. $\sqrt{\frac{3}{2}}$

4. $\sqrt{\frac{7}{6}}$

A biconvex lens is cut into two halves along (i) XOX' and (ii) YOY' as shown in the figure. Let \(f\), \(f'\) \(f''\) be the focal lengths of the complete lens, of each half in case (i), and of each half in case (ii), respectively.
   
Choose the correct statement from the following:

Light enters at an angle of incidence in a transparent rod of refractive index n. For what value of the refractive index of the material of the rod, will the light, once entered into it, not leave it through its lateral face whatsoever be the value of the angle of incidence?
1. $n$ $>\sqrt{2}$
2. 1.0
3. 1.3
4. 1.4

A rainbow is formed due to:

A concave mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be:

If the focal length of the objective lens is increased, then magnifying power of:

An air bubble in a glass slab with refractive index 1.5 (near-normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is:

Choose the correct mirror image of the figure:
    

1.		2.
3.		4.