In a half-wave uncontrolled rectifier with RL load why does the voltage spike when current reaches 0A?
Assume 1amp, 10uH and 100pF; the energy in the wiring will be moved into the capacitance of the wiring and the capacitance of the SCR.

These are the assumptions. What will be the resultant voltage?

Energy inductor == energy capacitance (assuming no losses)

0.5 * L * I^2 = 0.5 * C * V^2

L * I^2 = C * V^2

V^2 = (L/C) * I^2 and we assumed I was one.

Thus V = sqrt( L / C ) = sqt( 1uH / 100pF) = sqrt (1e-6 / 1e-10) = sqrt(1e-4)

V = sqrt(10,000) === 100 volts

and you are seeing 65 -- 85 volts.

Thus we have causality?