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MHT CET 2021 (20 Sep, Shift 2) · Spherical Surfaces & Thin Lenses

Spherical Surfaces & Thin Lenses question from MHT CET 2021 (20 Sep, Shift 2)

Q70MHT CET 2021 · 20 SEP · SHIFT 2Easy

Spherical Surfaces & Thin Lenses

A convex lens of focal length $f$ is used to form an image whose size is one fourth that of size of the object. Then the object distance is

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Answer: (b)

A diminished image by a convex lens is real: $u = -\frac{v}{1/4} = -4v$ .
$\frac{1}{v} + \frac{1}{4v} = \frac{1}{f} \Rightarrow v = \frac{5f}{4}$
$|u| = 4v = 5f$
So the answer is (b) 5f.

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