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Two lenses of power - 15 D and + 5 D are...

Two lenses of power - 15 D and + 5 D are in contact with each other. The focal length of the combination is

A

`+ 10`

B

`- 20`

C

`- 10`

D

`+ 20`

Text Solution

Verified by Experts

The correct Answer is:
A
`P = P_(1) + P_(2) = - 15 + 5 = - 10D`
`F = (1)/(P) = (1)/(-10) m = - 10 cm`
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