A students plots a graph between inverse of magnification 1/ m produced by a convex thin lens and the object distance u as shown in figure. What was the focal length of the lens used?

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Lens formula, v 1 ​ − u 1 ​ = f 1 ​ or v u ​ − 1 = f u ​ ⇒ m 1 ​ − 1 = f u ​ or m 1 ​ = ( f 1 ​ ) u + 1 this is the equation of a straight line whose slope f 1 ​ − c b ​ ∴ 1 − b c ​

Physics - Geometrical Optics Question with Solution | TestHub

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