Electrostatics

Electric charge
q = ne

Coulomb's law
F = k* q1 * q2 / r^2

Coulomb constant
k = 1 /(4π*ε_0)

Relative dielectric constant (permittivity)
ε = F_vak / F_apl

Electric field
E = F / q

Electric field of point charge in vacuum
E = k * q_0 / r^2

Electric field of point charge in environment
E_apl = k * q_0 / (ε * r^2)

Electric field outside charged sphere
E = k σ 4 π R^2 / r^2

Electric field outside charged sphere
E = kq/r^2

Electric field of infinite charged plane
E = k 2 π σ

Electric field of infinite charged plane
E = σ / (2 ε_0)

Electric field of condenser (capacitor)
E = 4 k π σ

Work in an electric field
A = F * Δ_d

Potential energy of a system of two point charges
W = k *q0 * q / (εr)

Work in an electric field - potential energy difference
A = W1 - W2

Potential of electrostatic field
φ = W / q

Voltage - potential difference
U = φ1 - φ2

The work of the charge transfer
A = q U

Electrostatic potential around a point charge
φ = k*q0 / (εr)

Electrostatic field strength
E = U / Δ_d

Total electric field
E = E0 - E1

Electric moment
p = q l

Electric capacitance
C = q / φ

Electric capacitance of sphere
C = ε R /k

Electric capacitance of two conductors
C = q / U

Electric capacitance of plane capacitor
C = ε * ε0 * S / d

Electric capacitance of spheric capacitor
C = 4 * π * ε * ε0 * R1 * R2 / (R2-R1)

Potential energy of a charged plane capacitor
W = q * E1 * d

Potential energy of a charged plane capacitor
W = q E d / 2

Potential energy of a charged plane capacitor
W = qU / 2

Potential energy of a charged plane capacitor
W = C*U^2 / 2

Potential energy of a charged plane capacitor
W = q^2 / (2C)

Potential energy of a charged plane capacitor
W = ε * ε0 * E^2 * V / 2

Potential energy of a charged plane capacitor
W = ε * ε0 * E^2 *S *d / 2

Energy density of electric field
ω_p = W / V

Energy density of electric field
ω_p = ε0 * ε * E^2 / 2