Name an instrument or toy which works by producing multiple reflections from three plane mirrors to form beautiful patterns.

Boojho planned an activity to observe an object A through pipes as shown in Fig. 16.8, so that he could see objects which he could not directly see.

(a) How many mirrors should he use to see the objects?

(b) Indicate the positions of the mirrors in the figure.

(c) What must be the angle with respect to the incident light at which he should place the mirrors?

(d) Indicate the direction of rays in the figure.

(e) If any of the mirrors is removed, will he be able to see the objects?

What is a periscope? How many mirrors are there in a periscope?

State one use of kaleidoscope.

State the information that you get about sunlight from the formation of a rainbow.

Name a device which works on the reflection of reflected light.

A student makes a device P by using three long and narrow strips of plane mirrors inclined at 60° to one another which enables him to see beautiful patterns made by pieces of coloured glass bangles. On the other hand, another student makes a device Q by using two plane mirrors arranged parallel to each other which helps him to see a football match clearly even when some very tall persons are sitting in front of him in the ground. What are P and Q?

A ray of light strikes a plane mirror XY at an angle of incidence of 65°, is reflected from this plane mirror and then strikes a second plane mirror YZ placed at right angles to the first mirror. What is the angle of reflection for the mirror YZ?

State the various uses of a periscope.

Name an instrument or toy which works by producing multiple reflections from three plane mirrors to form beautiful patterns.

State whether the following statements are true or false:

(a) The moon is an illuminated object.

(b) Diffuse reflection means the failure of the laws of reflection of light.

(c) In a kaleidoscope, a pattern seen once can never be seen again.