voltage across a inductor
\begin{equation} V = \epsilon = -L \dv{I}{t} \end{equation}
this is kind of a formulation of faraday’s law.
\begin{equation} I(t) = \frac{V_0}{R_1} (1-e^{\frac{-t}{\frac{L}{R}}}) \end{equation}
energy stored in an inductor
\begin{equation} E = \frac{1}{2} LI^{2} \end{equation}