# The two lenses of an achromatic doublet should have :

(1) equal powers

(2) equal dispersive powers

(3) equal ratio of their power and dispersive power

(4) sum of the products of their power and dispersive power should be equal to zero.

## 1 Answer

(4) sum of the products of their power and dispersive power should be equal to zero.
answered Nov 7, 2013 by

2 answers

1 answer

1 answer

1 answer

1 answer

1 answer

1 answer