Q. Which of the following is the reason behind when one enters a dark room; he is not able to see anything but after some time his vision improves? (UPSC Prelims 1983)
Answer: The pupil of the eye dilates
Notes: Our eyes cannot see everything clearly when we enter a dark room from a bright light. This is due to the reason that in dark room the pupil is large so when we come out in bright light, a large amount of light enters our eyes and we feel glare.