Electric Charges and Fields — Class 12 CBSE Physics revision notes
A 4-page visual revision sheet for Electric Charges and Fields, written for Class 12 CBSE Physics. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
What this Electric Charges and Fields sheet covers
- Charge
- Force
- Field
- Like charges vs unlike charges
- Like charges
- Unlike charges
- Charge, properly
- Coulomb's law
- force between two point charges
- Coulomb's constant
- vector form, direction along the line joining them
- the pair, always
- Superposition principle
- net force from many charges
- Electric field
- defined at a point
- field of a point charge q, at distance r
- Field line rules
- Electric dipole
- dipole moment, − to + charge
- field on the axis (r >> a)
- field on the equator (r >> a)
- torque in a uniform field
- Dipole in a uniform field
- Flux and Gauss's law
- flux through an area
- Gauss's law, any closed surface
- Three standard results
- infinite line, linear density λ
- infinite sheet, surface density σ
- charged shell, outside (r>R)
- charged shell, inside (r<R)
- Field of a ring, an arc, a disc
- ring of charge Q, field on the axis
- that field peaks at
- arc, half-angle α, at its centre
- disc of charge, field on the axis
- Units and dimensions
- q charge
- E electric field
- φ flux
- ε_0 permittivity
- Symbols
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Physics chapter by chapter against your real exam dates and free hours, and when the plan reaches Electric Charges and Fields the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.