Current Electricity
Class 12 · Current Electricity

Potentiometer

ε = kℓ. Slide jockey to find balance length on long wire.

Run simulation

Key Notes

01

Measures EMF without drawing current — the gold standard for cell EMF.

02

Set up potential gradient k = V_driver / L_wire; balance when galvanometer reads zero.

03

ε = k · ℓ where ℓ is balance length.

Formulas

Balance

k = V_driver/L_wire.

Important Points

Driver cell EMF must exceed test cell EMF.

More accurate than voltmeter because at balance no current flows through test cell.

Potentiometer 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.