Question

Draw a ray diagram to show the formation of a rainbow in the sky. On this diagram mark A – where dispersion of light occurs, B – where internal reflection of light occurs and C – where refraction of light occurs. List two necessary conditions to observe a rainbow.

Consider the following statements in the context of human eye : (a) The diameter of the eye ball is about 2.3 cm. (b) Iris is a dark muscular diaphragm that controls the size of the pupil. (c) Most of the refraction for the light rays entering the eye occurs at the crystalline lens. (d) While focusing on the objects at different distances the distance between the crystalline lens and the retina is adjusted by ciliary muscles. The correct statements are –

What is meant by power of accommodation of the eye?

The human eye can focus on objects at different distances by adjusting the focal length of the eye lens. This is due to