A beam of light consisting of consists of three. namely red (R), Green (G) and yellow (Y) on the prism as shown below. Complete the diagram to show refracted and emergent ray.

When we place a glass prism in the path of a narrow beam of white light a spectrum is obtained. What happens when a second identical prism is placed in an inverted position with respect to the first prism? Draw a labelled ray diagram to illustrate it.

A person can comfortably read a book but finds it difficult to read the number on a bus parked 5 m away from him. Name the type of defect of vision he is suffering
from. Which type of lens should be used in his spectacles to correct his vision?

Draw ray diagrams each showing:
Myopic eye.

Nocturnal animals (animals which sleep during the day and come out at night) tend to have wide pupils and lot of rods in their retinas. Suggest reasons for this.

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

Name the cells on the retina of an eye which are sensitive to

1. Dright light.
2. Dim light.
3. Sensation of colour.

Where are light-sensitive cells present in abundance and give their function?

The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?

Write the function of each of the following parts of human eye.

1. Cornea.
2. Iris.
3. Crystalline lens.
4. Ciliary muscles.