Light

Q 1.

State the laws of reflection.

Q 2.

What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

Q 3.

(a)Find out the position of the image of an object situated at A in the plane mirror (Fig. 16.21).(b)Can Paheli at B see this image?(c)Can Boojho at C see this image?(d)When Paheli moves from B to C, where does the image of A move?

Q 4.

Gurmit wanted to perform Activity 16.8 using a laser torch. Her teacher advised her not to do so. Can you explain the basis of the teacher's advice?

Q 5.

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.

Q 6.

Boojho stands at A just on the side of a plane mirror as shown in Fig. 16.20. Can he see himself in the mirror? Also can he see the image of objects situated at P. Q and R?

Q 7.

Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the laws of reflection?

Q 8.

Describe the construction of a kaleidoscope.

Q 9.

Explain how you can take care of your eyes.

Q 10.

Describe an activity to show that the incident ray, the reflected ray and the normal at the point of incidence lie in the same plane.

Q 11.

Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room? Explain.

Q 12.

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