Electrostatic Potential & Capacitance
Class 12 · Electrostatic Potential & Capacitance

Dielectric Breakdown

Each dielectric has a breakdown E_max. Above it, the dielectric arcs.

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Key Notes

01

Each dielectric has a maximum field E_max it can withstand before ionising and conducting.

02

Breakdown produces a spark (arc) — useful in spark plugs, harmful in capacitors.

03

Air: ~3 MV/m, mica: ~100 MV/m, glass: ~14 MV/m.

Formulas

Max V

Working voltage rating of capacitor.

Important Points

Capacitor data sheets specify V_max — exceeding it destroys the device.

Higher κ doesn't always mean higher E_max — they are independent properties.

Dielectric Breakdown 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.