Ray Optics and ...

Twinkling of stars is due to

Twinkling of stars is on account of

The sky is blue because

The relation between $$u, v$$ ( u is the object distance and v is the image distance )  and f for mirror is given by:

The bending of light ray after passing through a medium is commonly known as :

Choose the correct relation between u, v and r for a spherical mirror:

A convex lens magnifying glass is of-

A lean boy named Ramesh placed a glass slab of refractive index $$\dfrac{3}{2}$$ on his photograph. He felt it more interesting as his face appeared bigger than the original size when observed from the top of the glass slab. He also observed that the photo appears at a height of $$1.5$$ cm from the bottom. He then placed another glass cube made of different material and having the same thickness over the first glass cube. Now, he himself started to laugh by seeing his photograph as it appeared still bigger than the previous. When observed from the top the photograph appears to be at a height of $$4$$ cm from the bottom. Determine the refractive index of the second glass cube.

A vessel of water is $$2 m$$ deep. How deep will it appear if looked vertically downward?

$$\displaystyle \left [ _{a}{\mu }_{w} = \frac {4}{3} \right ]$$

The middle point of a spherical mirror is called