Question

A convex lens made of material of refractive index n 2 is kept in a medium of refractive index n1. A parallel beam of light is incident on the lens. Compare the path of rays of light emerging from the convex lens if (i) n1 < n2 (ii) n1 = n2 (iii) n1 > 1.

Answer 1

When $n_1<n_2$, light goes from rarer to denser medium. Therefore, on passing through a convex lens, it converges,

Ref. image

(i) When $n_1=n_2$, there is no change in medium. Therefore, no bending or refraction occurs as shown in figure.

(ii) When $n_1>n_2$, light goes from denser to rarer medium. Therefore, no passing through a convex lens, it diverges as shown in figure.