Question

1. What will happen to the focal length to the following substance when they are immersed in water ?

a) concave mirror b)convex mirror

2. What change will happen if the following substance is immersed in water?

a) concave lens b) convex lens

Answer 1

Hi Saravana!

(1) The focal lengths of mirrors will not change when immersed in water. This is because, mirrors work under the principle of reflection of light.

(2) The focal lengths of lenses will change when immersed in water. Lenses are working according to the principle of refraction of light. The change depends on the refractive index of the water and the refractive index of the material of the lens.

Cheers!!