Question

# A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of he combination, is :

A
+6.67D
B
6.5D
C
1.5D
D
+6.5D
Solution
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#### Given,f1=+40cmf2=−25cmPower, P=1fThe power of combination,P=1f1+1f2P=100+40cm+100−25cmP=−1.5DThe correct option is C.

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