class 8 -light
1. What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

2.How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 cm?

3.Two mirrors meet at right angles. A ray of light is incident on one at an angle of 30° as shown in Fig. 16.19. Draw the reflected ray from the second mirror.

4. Fill in the blanks in the following.

(a) A person 1 m in front of a plane mirror seems to be ________ m away from his image.
(b) If you touch your ________ ear with your right hand in front of a plane mirror, it will be seen in the mirror that your right ear is touched with your _________.
(c) The size of the pupil becomes ________ when you see in dim light.
(d) Night birds have _________ cones than rods in their eyes.

5. Explain the term spectrum. Why does a glass prism split white light into its constituent colour?

6  What do you mean by refraction of light? In which direction will light bend when travelling from an optically rarer to denser medium?

7   Distinguish between myopia and hypermetropia. Draw diagrams top show how these defects can be corrected by using suitable lenses...