Question

give reason .. we feel blinded for a short while entering a dark room when we come from bright light

Answer 1

In a bright room, our eyes contract so as to let in only adequate point of light, when we enter a dark room, our eyes need time to adjust to the low light.

Answer 2

When you are in the dark, the pupil gets dilated to allow more light into the retina so that you can see. When you are in a bright area, the pupil constricts so that not much light than that needed reaches the retina. Our retina will need a definite amount of light for proper vision. When you are in a bright room, the pupil has constricted itself, and on sudden darkness, it would take certain time for the pupil to dilate so that you will be able to see. The rods and cones in our eye are less sensitive and send lesser amount of neural impulses to the brain when we are in a bright area. On entering the dark room, they will need to become more sensitive, and this adjustment does take some time. That is the sole reason for the momentary difficulty in having a proper vision!

I hope this helped you!!