FormulaBoltzmann distribution function (Probability, Energy, Temperature) $$ P(W) ~=~ \mathrm{e}^{ -\frac{ W - \mu }{ k_{\text B} \, T}} $$
FormulaSpherical Capacitor (Capacitance, Radius) $$ C ~=~ \frac{4\pi \, \varepsilon_{\text r} \, \varepsilon_0}{\frac{1}{R_1} ~-~ \frac{1}{R_2}} $$
FormulaCylindrical Capacitor (Capacitance, Radius) $$ C ~=~ 2\pi \, \varepsilon_0 \, \varepsilon_{\text r} \, l \, \frac{ 1 }{\ln{ \left( \frac{R_2}{R_1} \right) }} $$
FormulaCharging capacitor (Current, Capacitance, Resistance, Time) $$ I(t) ~=~ I_0 \, \mathrm{e}^{-\frac{t}{R\,C}} $$
