Question

Write scientific reason.

Farsightedness, this defect can be corrected by using convex lens.

Answer 1

1. Farsightedness arises due to slight flattening of the eyeball causing in decrease in the distance between the eye lens and the retina or due to decrease in the curvature of the cornea and eye lens resulting in decreased converging power.
2. As a result, light from a distant object arriving at the eye-lens gets converged at a point behind the retina.
3. When a convex lens of suitable focal length is placed between the eye and object, due to the converging effect of the convex lens, the image gets focussed on the retina.
   Thus, farsightedness can be corrected by using spectacles with a convex lens.