This circuito proceso Lenz's Las which states that an inductor generales a voltage which opooses to current changes.
Withvthe button closed, the 8V from the voltage source is not enough to lit the bulb, but when the button is pushed the circuit is open and the current drops to 0A in a very short time, given by the time constant L/R. The inductor will try to keep the current value, so it will generate a -64V voltage, enough to lit the bulb forma a very short time.
