3 2 4 2 5 85 A convex lens of focal length f and dispersive

Last updated: 6/24/2023

3 2 4 2 5 85 A convex lens of focal length f and dispersive power is combined with a concave lens of focal length f2 and dispersive power 2 is such a way that an achromatic doublet of focal length 40 cm is obtained If respectively 1 3 40 3 40 3 per 20 20 00 02 2 3 1 then f and f2 in cm are 2 20 4 20 40 we we