• This question does not make sense. If a resistor is in series with the coil, and $V$ is voltage across the resistor, then current is proportional to $V$ and EMF, given by $-LdI/dt$, should behave as derivative of $V(t)$. But there is is no trace of this in the graph, the EMF seems to copy the function $V(t)$. How did you determine EMF? – Ján Lalinský Jun 28 '18 at 8:34