Question

Noopur needs a lens of power -4.5 D for correction of her vision .

(a) Draw ray diagrams showing the (1) defected eye and (2) correction for this defect.
(b) What are causes of this defect.

Answer 1

The retina of the human eye has a large number of cone-shaped and rod-shaped cells. The rods respond to the intensity of light and the cones to the colours. These help us to perceive colours.The ability of the eye to focus on near and distant objects, by adjusting its focal length, is called the accommodation of the eye.microscope is an optical instrument which is used to see the finer details of tiny objects, and a telescope is used for viewing distant objects clearly.The amount of light entering the eye is controlled by the pupil. If the intensity of the outside light is low, then the pupil expands to allow more light to enter the eye. If the outside intensity is high, then the pupil contracts so that less light enters the eye.