A convex lens of focal length 'F' produces a real image 'n' times the size of the object. The image distance…

A convex lens of focal length 'F' produces a real image 'n' times the size of the object. The image distance is
  1. $\mathrm{F}(\mathrm{n}+1)$
  2. $\mathrm{F}(\mathrm{n}-1)$
  3. $\frac{\mathrm{F}}{(\mathrm{n}+1)}$
  4. $\frac{\mathrm{F}}{(\mathrm{n}-1)}$

Solution

$\frac{v}{u}=(-n) \quad \therefore v=(-u n)$ $\therefore \quad \frac{1}{F}=\frac{1}{v}-\frac{1}{u}$ $\frac{v}{F}=1-\frac{v}{u}=1+n$ $\therefore v=F(1+n)$

Asked in: MHT CET 2020 (15 Oct Shift 1)

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