Key Concepts and Notations
- W = Work done, unit: joules (J)
- V = Electric potential, unit: volt (V)
- C = Capacitance, unit: farad (F) (1 F = 1 C V–1)
Work Done by an External Force
Formula: WRP = ∫RP (Fext ⋅ dr)
Potential Energy Difference
Formula: ΔU = UP - UR = WRP
Relation Between Electrostatic Potential and Potential Difference
Formula: VP - VR = (UP - UR) / q
In Case of Infinity
Formula: W∞P = V
Force Between Charges
Formula: F = k (Q1 Q2) / r2
Potential at a Point Due to a Charge
Formula: V(r) = k Q / r
Potential Due to a Dipole
Formula: V = (k p cos θ) / r2
Electric Field at the Surface of a Charged Conductor
Formula: E = σ / ε0
Polarization (P)
Formula: P = ε0 χe E
Capacitance of a Capacitor
Formula: C = Q / V
Relationship Between V, E, and d
Formula: V = E d = (1 / ε0) Q d / A
Capacitance with Dielectric
Formula: C = (ε0 K A) / d
Capacitor in Series and Parallel
Series: 1/C = 1/C1 + 1/C2 + ... + 1/Cn
Parallel: C = C1 + C2 + ... + Cn
Work Done in a Capacitor
Formula: W = 1/2 C V2 = 1/2 Q V
Energy Stored in a Capacitor
Formula: U = 1/2 (Q2 / C) = 1/2 Q V = 1/2 C V2
Energy Density of an Electric Field
Formula: u = 1/2 ε0 E2
Download the Complete Formula List
For easy reference, you can download the full list of formulas here: