A point object is moving along the principal axis of a concave mirror with uniform velocity towards the pole. Initially, the object is at infinite distance from pole on right side of the mirror as shown. Before the object collides with the mirror, how many times the distance between the object and its image is $40 \mathrm{cm}$?

 

 

The positions of the object $O$ (real or virtual) and the image $I$ (real or virtual) with respect to the optical axis of a spherical mirror are shown. Then select the possible mirror and its position to realise it.

One side of a glass slab is silvered as shown. A ray of light is incident on the other side at an angle of incidence, $\mathit{ }i\text{=}45°$. If the refractive index of glass is $1.5$, the deviation of the ray of light from its initial path when it comes out of the slab is

A rectangular metal tank is filled to the top with an unknown liquid. An observer on an eye-level can just see the corner $E$, from the top of the tank; a ray that refracts towards the observer at the top surface of the liquid is shown. The refractive index of the liquid will be

A plane mirror is placed at the bottom of the tank containing a liquid of refractive index, $\mu$. $P$ is a small object at a height, $h$ above the mirror. An observer, $O$ vertically above $P$ outside the liquid, sees $P$ and its image in the mirror. The apparent distance between these two will be