# How exactly does a bulb light up?

A typical value for the electron drift velocity in a copper wire is $10^3\ \mathrm{m\ s^{-1}}$. In the circuit below, the length of the copper wire joining the negative terminal of the batter to the lamp is $0.50\ \mathrm{m}$.

(i) The switch S is closed. Calculate the time it would take for an electron to move from the negative terminal of the battery to the lamp.

(ii) The lamp lights in a time much less than that calculated in (e)(i). Explain this observation.

In the second part, I can't imagine the situation. I reckon that not all electrons travel with a drift velocity, so the faster ones reach the bulb and make it glow.

But how exactly does this lighting happen? The electron comes in contact with the circuitry and lights up the bulb, or is it because of the electric field?