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प्रश्न
Which type of lens has (a) a positive power, and (b) a negative power?
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उत्तर
(a) Convex lens has positive power.
(b) Concave lens has negative power.
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संबंधित प्रश्न
Calculate the focal length of a corrective lens having power +2D.
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(b) state the nature of lens Y.
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(2) an erect image of the tree on the lens.
(3) no image as the screen has been removed
(4) an inverted image of the tree at the focus of the lens.
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