Question

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?

Answer 1

Explanation:

P is a Kaleidoscope whereas Q is a Periscope.

Answer 2

The device P is kaleidoscope

The device Q is periscope

Kaleidoscope:

• It is an optical instrument.
• The principle of this instrument is formation of multiple image through reflection when mirrors are placed in a inclined angle.
• The number of images formed is given by the formula:
• $N=\left(\frac{360^{\circ}}{x}-1\right)$
• Where, x  is angle of the mirror.
• Here, the angle is 60°, so, the number of image formed is 59.
• The pattern of the image is never repeated.

Periscope:

• It is an optical instrument.
• The principle of this instrument is reflection of light from one mirror to another which are arranged parallel to each other.
• It gives image at higher level than the level of our eyesight.
• This instrument is majorly used in submarine to view the objects in the surface or surrounding and it is also used by army people during war.