Electric Charges & Fields
Class 12 · Electric Charges & Fields
Charge on Connected Spheres
Same potential ⇒ Q ∝ R, σ ∝ 1/R. Smaller sphere has higher field.
Key Notes
01
Two conducting spheres connected by a wire reach the same potential V.
02
V = kQ/R same on each → Q ∝ R; σ = Q/(4πR²) ∝ 1/R.
03
Smaller sphere has higher σ and stronger surface E.
Formulas
Charge ratio
Connected spheres at common V.
σ ratio
Smaller R → higher σ.
Important Points
Foundation of why lightning conductors work.
Same logic explains why metal protrusions (door knobs) become sites of static spark.
Charge on Connected Spheres 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.