Allow two lights rays to incident on a screen after passing through two slits. What happens to the pattern on the screen when the whole apparatus is dipped in water.

Pass sunlight through a prism and allow it to fall on a screen . What are the coloure seen on the screen ?

How many times does a ray of light undergo refraction when it passes through a water droplet ?

The path of light rays through a convex lens when it is placed in two different media is shown in the figure. What is the relation between the refractive indices mu, mu_1 and mu_2 ?