When a person enters a dark room from a bright light area, so he does not see clearly for some time, but later gradually he starts seeing things. The reason for this is
When a person enters a dark room from a bright area, initially they do not see clearly due to the slow adaptation of their eyes to low light conditions. Over time, their eyes adjust through a process called dark adaptation, where the sensitivity of the retinal cells increases, allowing better vision in darkness.
Share
When a person enters a dark room from a bright light area, they experience impaired vision initially because their eyes are adapted to the bright light. The correct answer is [D] Adaptation of the eyes to darkness over some time. In bright light, the pupils constrict and rhodopsin (a light-sensitive pigment) in the retina becomes bleached. As the person moves into darkness, the pupils dilate to allow more light to enter the eyes, and rhodopsin begins to regenerate, a process known as dark adaptation. This adaptation involves the eyes becoming more sensitive to low light conditions over time, allowing the person to gradually see better in the dark room. Option A, change in the size of the pupil, and option B, change in the diameter and focal length of the lens, are mechanisms related to adjusting to different light intensities but do not explain the gradual improvement in vision in darkness. Option C, decolorization and restaining of rhodopsin, is not a recognized physiological process; instead, rhodopsin regeneration occurs. Therefore, the reason a person gradually starts seeing better in a dark room after entering from a bright area is due to the adaptation of their eyes to darkness over some time (option D).