Will light turn on in a closed circuit for a moment if a diode stops electric current after light source is reached?
In a very technical, nit-picky kind of way, yes… sort of. The depletion layer of a reverse-biased diode has a capacitance. If we assume that capacitor is discharged at t=0, then some current will flow briefly as it charges to the voltage of the battery.

However, that capacitance is very small for most diodes. For instance, it's about 15 pF for a 1N4001 diode. If we assume a 5V source and a 100Ω resistance, this takes about 10 ns to charge; simulate the circuit below to see for yourself.







simulate this circuit &ndash; Schematic created using CircuitLab