An achromatic combination of lenses is formed | vedclass

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(C) For an achromatic combination,the condition is given by $\frac{\omega_1}{f_1} + \frac{\omega_2}{f_2} = 0$.Here,$\omega_1$ and $\omega_2$ are the d

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$1$ convex lens and $1$ concave lens

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(C) For an achromatic combination,the condition is given by $\frac{\omega_1}{f_1} + \frac{\omega_2}{f_2} = 0$.Here,$\omega_1$ and $\omega_2$ are the dispersive powers of the two lenses,and $f_1$ and $f_2$ are their respective focal lengths.Since the dispersive powers $\omega_1$ and $\omega_2$ are always positive,the focal lengths $f_1$ and $f_2$ must have opposite signs for the sum to be zero.This implies that one lens must be convex (positive focal length) and the other must be concave (negative focal length).Therefore,an achromatic combination is formed by joining $1$ convex lens and $1$ concave lens.

An achromatic combination of lenses is formed by joining

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