Question

what is the focal length and power of the combination of a convex lens of focal length 40 centimetre placed in contact with a concave lens of focal length 20 centimetre ​

Answer 1

Answer:

A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination is. Solution : P=1f=1f1+1f2=10.4+1-0.25=-1.5diopter.

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