Question

Why does it take sometime to see object in a dim room when you enter the room from a bright sun shine?

Answer 1

When we pass from a brightly lighted area ( here from bright sunshine) we experience difficulty in seeing objects for a short while. Slowly, our vision is improved . This improvement is called dark adaptation. This change due to :-

1. REGENERATION OF RHODOPSIN, the pigment of rods , which was earlier broken down due to bright light.

2. DIALATION OF PUPIL permitting more light to enter our eyes.

Answer 2

• Iris is the part of eye which controls the amount of light entering our eye. It takes time to adjust light intensity.
• The size of pupil changes as light intensity changes. In bright light the pupil size is small due to which less amount of light enters in dim room.