A parallel beam of white light falls on a convex lens. Images of blue, yellow and red light are formed on other side of the lens at a distance of $0.20\ m,\ 0.205\ m$ and $0.214\ m$ respectively. The dispersive power of the material of the lens will be

Question

Dr. Abubacker · Accepted Answer

(c) For a lens $f_{r} - f_{v} = \omega\ f_{y}$
$\Rightarrow \omega = \frac{f_{r} - f_{v}}{f_{y}} = \frac{0.214 - 0.200}{0.205} = \frac{14}{205}$

Q. A parallel beam of white light falls on a convex lens. Images of blue, yellow and red light are formed on other side of the lens at a distance of $0.20\ m,\ 0.205\ m$ and $0.214\ m$ respectively. The dispersive power of the material of the lens will be

Explanation

Reviewed by Dr. Abubacker

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