Question

A convex lens of focal length x is put in contact with a concave lens of focal
length y. The equivalent focal length of the combination is​

Answer 1

Answer:

Given , focal length of convex lens f1=f and focal length of concave lens, f2=−f

The focal length of combination, when two lenses are in contact is given by

1f=1f1+1f2 ……(i)

Subsitiuting given value in Eq.(i) , we get

rARr 1f=1f−1f=0⇒f=∞

Hence , the equivalent focal lenght of the combintions is infinity.

Explanation:

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Answer 2

Answer:

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