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Two thin lenses of power + 3 D and - 1 D...

Two thin lenses of power `+ 3 D and - 1 D` are held in contact with each other. Focal length of the combination is :

Text Solution

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`P = P_(1) + P_(2) = +3 - 1 = 2 D`
`F = (100)/(P) = (100)/(2) = 50 cm`
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