Electrostatic Potential & Capacitance
Class 12 · Electrostatic Potential & Capacitance
Battery Removal Case
Insert dielectric with battery on/off — different physics. Compare side-by-side.
Key Notes
01
Connected battery: V fixed. Insert dielectric → Q increases (battery does work).
02
Battery removed: Q fixed. Insert dielectric → V drops by κ; U drops by κ.
03
These are two distinct physical scenarios with different energy bookkeeping.
Formulas
V fixed
Battery supplies extra energy.
Q fixed
Energy decreases — slab pulled in does work.
Important Points
JEE loves to ask which case is which — read carefully.
Net charge on plates is conserved in Q-fixed case (because battery is disconnected).
Battery Removal Case notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 12 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.