Question

A compound lens is made of 2 lenses in contact having powers+12.5d and -2.5d .find the focal length and power combination

Answer 1

Total power = p1+p2
= 12.5- 2.5
= 10
to find focal length
P = 1/f
10 = 1/f
f = 1/10
f = 0.1

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