## Question

The dispersive powers of crown and flint glasses are 0.02 and 0.04 respectively. Find the focal length of the convex lens of crown glass which forms achromatic doublet with a concave lens of flint glass of focal length 80 cm.

### Solution

+40 cm

The condition for achromatism of two lenses in contact is

Where symbols have their usual meanings.

#### SIMILAR QUESTIONS

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