Physics · Class 12 · Chapter 2
Electrostatic Potential and Capacitance
13 lessons 109 min 2 simulations
This chapter swaps forces and fields for energy. Because the electrostatic force is conservative, every point near a charge can be given a potential (work per unit charge), and every arrangement of charges a potential energy. The chapter finds the potential of a point charge, a dipole and a group of charges, links potential to field through equipotential surfaces, then turns to conductors, dielectrics and the capacitor: its capacitance, the effect of a dielectric, series and parallel combinations and the energy it stores.
What the exam asks
NEET asks for the potential at a point from several charges (a scalar sum), the work done in moving a charge between two points, the potential energy of two or three charges, and the energy of a dipole in a field. The capacitor half is heavily tested: C = ε₀KA/d, what changes when a dielectric goes in with the battery connected or removed, series and parallel networks, and U = ½CV². Marks are lost by adding potentials as vectors, by dropping the sign of a charge, and by mixing up which quantity stays fixed when the battery is removed.
Lessons
13 lessons · 109 min
1Electrostatic potentialNCERT §2.1 to §2.37 min2Potential due to a dipoleNCERT §2.47 min3Potential due to a system of chargesNCERT §2.57 min4Equipotential surfacesNCERT §2.67 min5Potential energy of a system of chargesNCERT §2.76 min6Potential energy in an external fieldNCERT §2.87 min7Electrostatics of conductorsNCERT §2.98 min8Dielectrics and polarisationNCERT §2.107 min9Capacitors and the parallel plate capacitorNCERT §2.11 and §2.127 min10Effect of dielectric on capacitanceNCERT §2.1311 min 1 sim11Combination of capacitorsNCERT §2.1410 min 1 sim12Energy stored in a capacitorNCERT §2.158 min13Chapter reviewMust-know facts, traps and formulas17 min