Question

Why does it take some time to see objects in a dim room, when you enter the room from bright sunlight outside?

Answer 1

This is caused by bleaching of the retinal pigment. As the pigment returns to normal, so too does sight. In daylight the eye's pupil constricts, thus reducing the amount of light entering after a flash. At night, the dark-adapted pupil is wide open so this blindness has a greater effect and lasts longer.