Electrostatic Potential & Capacitance
Class 12 · Electrostatic Potential & Capacitance

Effect of Dielectric

C' = κC₀. Toggle V-fixed (Q grows) vs Q-fixed (V drops).

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Key Notes

01

Inserting a dielectric of relative permittivity κ multiplies capacitance: C' = κC₀.

02

If battery stays connected (V fixed): Q increases by factor κ.

03

If battery disconnected (Q fixed): V drops by factor κ; energy U drops by κ.

Formulas

Capacitance

κ ≥ 1 always; vacuum κ = 1.

Energy with battery

Battery does extra work.

Energy with battery off

Some energy → work pulling slab in.

Important Points

Common dielectrics: air (1.0), paper (3.7), mica (6), glass (8), water (80).

Bound charges on dielectric surface partially cancel the field.

Effect of Dielectric 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.