Reflection & Mirrors question from MHT CET 2024 (2 May, Shift 2)

Answer: (c)

1. Real image: $m = -n = -\frac{v}{u} \Rightarrow v = nu$ (both negative).
2. Put $u = -x$, $v = -nx$, $f \to -f$ in $\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$: $\frac{1}{nx} + \frac{1}{x} = \frac{1}{f}$
3. $\frac{n+1}{nx} = \frac{1}{f} \Rightarrow x = \left(\frac{n+1}{n}\right)f$
4. So the answer is (c) $\left(\frac{n+1}{n}\right)f$.