Electromagnetic Induction and Alternating Current — Formula Sheet

φ_B = B · A · cosθ

ε = −dφ_B/dt

|ε_r| = N · (dφ_B/dt)

φ = LI

ε = −L(dI/dt)

L = μ₀N²A/ℓ

τ = L/R

φ₂ = MI₁

ε₂ = −M(dI₁/dt)

AC voltage

V = V_m·cosωt, AC current: I = I_m·cosωt, where V_m and I_m are peak (maximum) values.

RMS (Root Mean Square) values

V_rms = V_m/√2 ≈ 0.707·V_m and I_rms = I_m/√2 ≈ 0.707·I_m.

SI unit of magnetic flux is Weber (Wb); 1 Wb = 1 T·m².

Combined law

ε = -N(dφ_B/dt) — the negative sign embodies Lenz's law.