A concave lens made of a material of refractive index `n_1` is kept in a medium of refractive index `n_2`. A parallel beam of light is incident on the lens. Complete the path of rays of light emerging from the concave lens (i) `n_1 gt n_2` (ii) `n_1 = n_2` (iii) `n_1 lt n_2`.

Explanation

The paths of the emergent rays in the three cases are shown in Fig.
(b) As `n_1 gt n`, light goes from denser to rarer medium. Therefore, in passing through a concave lens, it converges instead of diverging, as shown in Fig.
(b) As `n_1 lt n`, light goes from rarer to denser medium. Therefore, in passing through a concave lens, it diverges as shown in Fig.
(c ) As `n_1 = n`, there is no change in medium on passing through a concave lens. Hence there is no bending/refraction. The rays continue along their original path, as shown in Fig.
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