A person walking in a dark corridor enters into a brightly lit room:(a) State the effect on the pupil of the eye.(b) How does this affect the amount of light entering the eye?

A person walking in a dark corridor enters into a brightly lit room:

(a) The effect on the pupil of the eye is that it gets contracted (becomes small) because the pupil remains large when the person was walking in a dark corridor. But as the person enters a brightly lit room, a large amount of light enters his eyes, due to which the person feels a glare in the eyes. After some time, adjusting itself according to the intensity of the surrounding light, the pupil starts contracting gradually.

(b) The amount of light entering the eye gets affected since the light starts reducing because of the contraction of the pupil of the eyes.

Explanation

 Pupil is a hole in the middle of the iris, which appears black because the light that passes through it, gets absorbed by the retina and is not reflected back. Its function is to control the amount of light entering the eye with the help of the iris so that it can be focused on the retina to begin the process of sight.

In low-light conditions, the iris expands the pupil to increase the amount of light entering the eyes, so that more light can reach the retina and make us able to see in dim or dark surroundings.

In bright conditions, the iris contracts the pupil to reduce the amount of light entering the eyes, so that too much light can't cause glare and discomfort to the eye, and even can't damage the lens and retina.