Two convex lens of focal length 20 cm and 25 cm are placed in contract with each other, then power of this combination is : <

Question

Two convex lens of focal length 20 cm and
25 cm are placed in contract with each other,
then power of this combination is :

1). +1D
2).-1D
3).+9D
4).-9D​

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Melanie 2 weeks 2021-09-09T14:47:20+00:00 1 Answer 0 views 0

Answers ( )

    0
    2021-09-09T14:48:44+00:00

    Answer:

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