Magnetic field in long straight coil

B=μrμ0N⋅IlB=\frac{\mu_r\mu_0N\cdot I}{l}

Induced Voltage

uind=−dΦmdtu_{ind}=-\frac{d\Phi_m}{dt}

Self induction in coil

uind=−L⋅didtu_{ind}=-L\cdot\frac{di}{dt}

Energy in coil

w=L⋅I22w=\frac{L\cdot I^2}{2}

Angular frequency

ω=2π⋅f=2πT\omega=2\pi\cdot f=\frac{2\pi}{T}

Instantaneous value, alternating voltage

u=u^⋅sin(ωt+α)u=\hat{u}\cdot sin(\omega t +\alpha)