Light - Exemplar Solutions 2
CHAPTER – 16
LIGHT
VERY SHORT ANSWER QUESTIONS
9. Name the part of the eye which gives colour to the eyes.
Ans: The Iris is the part of the eye which gives colour to the eyes.
10. Boojho while waving his hand very fast in front of his eyes, observes that his fingers appear blurred. What could be the reason for it ?
Ans: The impression of an image persists for about 1/16th of a second. So, if stationary images of a moving object are flashed at a rate faster than 16 images per second, then the eye perceive the object as moving.
11. How many times is a ray of light reflected by two plane mirrors placed parallel and facing each other ?
Ans: Infinite number of times.
12. The angle between incident ray and reflected ray is 60°. What is the value of angle of incidence ?
Ans: According to the law of reflection, angle of incidence is always equal to the angle of reflection.
Let equal of incident ray = reflected ray = x.
The angle of between incident ray and reflected ray is 60o i.e. 2x = 60o
Or x = 30o. i.e. angle of incident ray = 30o
13. The distance between the object and its image formed by a plane mirror appears to be 24 cm. What is the distance between the mirror and the object ?
Ans: Distance between the object and the image = distance between the object and mirror + distance between the mirror and image.
Distance between the object and mirror is equal to the distance between the mirror and the image = x.
2x = 24
x = 12.
So, the distance between mirror and object is 12 cm.
