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प्रश्न
A lens of focal length f is divided into two equal parts and then these parts are put in a combination as shown in the figure below.
- What is the focal length of L1?
- What is the focal length of the final combination?
उत्तर
(i) `1/"f" = (η -1) (2/"R")`
(ii) `1/"f"_1 = (η -1) (1/"R")`
F1 = 2f
`1/"f"_2 = (η -1) (2/"R")`
F2 = f
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