Describe the construction of a kaleidoscope.

Look into your friend’s eye. Observe the size of the pupil. Throw light on her eye with a torch. Observe the pupil now. Switch off the torch, and observe her pupil once again. Do you notice any change in the size of the pupil? In which case was the pupil larger? Why do you think it was so? In which case do you need to allow more light in the eye, when the light is dim or bright?

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

Yasir stands at A just on the side of a plane mirror as shown in figure. Can he see himself in the mirror? Also, can he see the image of objects situated at $\mathrm{P}, \mathrm{Q}$ and $\mathrm{R}$?

(a) Find out the position of the image of an object situated at $\mathrm{A}$ in the plane mirror (shown in figure below).
(b) Can Saba at $\mathrm{B}$ see this image?
(c) Can Yasir at $\mathrm{C}$ see this image?
(d) When Saba moves from $\mathrm{B}$ to $\mathrm{C}$, where does the image of $\mathrm{A}$ move.