Q5 of 27 Page 441

The focal length of a converging lens are fv and fr for violet and red light respectively.

Because focal length is inversely proportional to refractive index. And, refractive index is inversely proportional to .So, keeeping other parameters same,we get:


f ∝ (λr- λv)


So, fv<fr . Hence, option (C) is correct.

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