Question

iii. A student uses spectacles of number -2 for
seeing distant objects. Commonly used
lenses for her/his spectacles are
(A) bi-concave
(B) double concave
(C) concavo-convex
nvexo-concave​

Answer 1

Answer:

double concave is the spectacle used

Answer 2

Answer:

The correct option is Option D i.e. Convexo-concave.

Explanation:

This type of lens i.e. Convexo-concave lens is lens which is an actually concave lens, with the Centre of the lens being thinner than its surroundings. But, one of a surfaces of a lens is concave and the other one is convex.

This type of lens is used to correct a myopia in students because they are able to diverge light rays by a bit, which makes the correct focusing of the light rays after subsequent refraction through the refractive mechanisms of the eye directly on retina.