Electrostatic Potential and Capacitance: The Exact Questions RBSE Keeps Asking (Chapter 2)

If you have gone through the last decade of RBSE Class 12 Physics papers, you will notice Chapter 2 rarely surprises anyone. It belongs to Unit I – Electrostatics and reliably contributes around 6–8 marks to the paper every year — enough that skipping it is simply not an option. What changes from year to year is small; the shape of the questions stays remarkably steady.

You can expect a quick 1-mark opener — a definition or a diagram, most often the equipotential surface for a positive charge, which has already been asked in 2016, 2021 and 2024. Then come the 1.5 to 2-mark numericals on electric potential due to a point charge or a charged spherical shell, and the potential energy of a system of charges. The heavy marks sit in the 4-mark long answers, which almost always ask you to derive the capacitance of a parallel-plate capacitor (with or without a dielectric of constant K), or to prove a result about capacitors combined in series and parallel.

So the smart way to revise this chapter is not to read it end to end, but to practise the questions RBSE actually repeats. The five questions above — and the ten in the free sample PDF — are taken straight from real board papers and tagged with the exact years they appeared, so you can see for yourself what the full RBSE Physics chapterwise PYQ book offers before you decide to buy it.