A bulb lights up almost instantly when connected to a circuit. Are electrons lightning-fast?
MYTH: A bulb lights up when electrons from the negative terminal reach the bulb
FACT: Bulb lights up due to a constant flow of charges through the filament, and not because of electrons from the cell reaching it
When a bulb is connected to a battery, a flow of electrons is started, such that, if an electron from the negative terminal moves to the connecting wire, a free electron from the wire moves to the positive terminal of the cell, at the same time. Thus, it's the flow of electrons, that we call electric current which finally lights up the bulb.