CBSE 2025 · Region 6 · Set 1 · Q2 · 1 mark
If $\displaystyle \mathrm{R}_{s}$ and $\displaystyle \mathrm{R}_{p}$ are the equivalent resistances of $\displaystyle \mathrm{n}$ resistors, each of value $\displaystyle \mathrm{R}$, in series and parallel combinations respectively, then the value of $\displaystyle \left(\mathrm{R}_{s}-\mathrm{R}_{p}\right)$ is :
Official answer
From CBSE’s own marking scheme for this paper.
(C)
$\displaystyle \left(\frac{\mathrm{n}^{2}-1}{\mathrm{n}}\right) \mathrm{R}$
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CBSE Class 12 Physics past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.