Question
Tue October 02, 2012 By: Shelly
 

a converging lens is kept coaxially in contact with a diverging lens, both the lenses being of equal focal lengths. what is the focal length of the combination?

Expert Reply
Wed October 03, 2012
Let the focal length of both the lenses be f.
Focal length of the combinationis F given by
1/F = (1/f)+(1/-f) = 0
or, F is infinity.
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