(i) What is myopia? State the two causes of myopia. With the help of labelled ray diagrams show
(a) The eye defect myopia
(b) Correction of myopia using a lens.
(ii) Why is the normal eye unable to focus on an object placed within 10 cm from the eye?
(i) Myopia or near sightedness where a person can see the objects near to him but cannot see farther objects distinctly.
CAUSES: 1. Decreases in focal length of the eye lens.
2. Elongation of the eyeball.
(ii) Human eye lens tends to adjust the focal length he/she can see this is called accommodation of eye lens. This accommodation lies between 25cm to infinity.
A person can’t focus at 10cm because it lies outside the range of accommodation and focusing on this length may have bad impact on eyes that is a strain.