Electric Charges & Fields
Class 12 · Electric Charges & Fields
Gaussian Surface — Sphere
E = 0 inside a uniformly charged shell, kQ/r² outside. Plot with live cursor.
Key Notes
01
Uniformly charged spherical shell: outside, E = kQ/r² (acts like point charge at center).
02
Inside the shell: E = 0 everywhere (a key Gauss's law result).
03
For solid uniform sphere of charge: E inside ∝ r, E outside same as point charge.
Formulas
Shell, outside
r > R.
Shell, inside
r < R.
Solid sphere, inside
Linear in r.
Important Points
These results are fundamental for satellites, planets (gravity), conductors.
At r=R there's a discontinuity for the shell: E jumps from 0 to kQ/R².
Gaussian Surface — Sphere 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.