The minimum power of the eye lens is 40 D. If the far point of the normal eye is infinity. Find the size of the eye ball.

No rainbow could be observed from the surface of Moon by the astronauts. What could be the possible reason?

When a light ray passes obliquely through the atmosphere in an upward direction how does its path generally change?

A person got his eyes tested. The optician prescription for the spectacle read.

Left eye = -3 D are right eye = -3.5 D

Discuss the defects of which person is suffering.

The power of a lens is + 1.5 D. Name the type of defects vision that can be corrected by using this lens. Find the focal length of the lens.