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MHT CET 2024 (3 May, Shift 2) · Spherical Surfaces & Thin Lenses

Spherical Surfaces & Thin Lenses question from MHT CET 2024 (3 May, Shift 2)

Q45MHT CET 2024 · 3 MAY · SHIFT 2Medium

Spherical Surfaces & Thin Lenses

A convex lens of focal length ' ff ' produces a real image whose size is ' nn ' times the size of an object. The distance of the object from the lens is

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Answer: (d)

  1. Real image: m=−nm = -n, so with u=−xu = -x, v=nxv = nx.
  2. Lens formula: 1v−1u=1nx+1x=1f\frac{1}{v} - \frac{1}{u} = \frac{1}{nx} + \frac{1}{x} = \frac{1}{f}
  3. n+1nx=1f⇒x=fn+1n\frac{n+1}{nx} = \frac{1}{f} \Rightarrow x = f\frac{n+1}{n}
  4. So the answer is (d) f(1+1n)f\left(1 + \frac{1}{n}\right).
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