[georgyo]

What is c/2?

1/c was because the distance between the lightbulb and the battery was 1 meter. m / m/s = s

With c as the numerator, I don't even know what the units of that 2 would be? m/s²?

[ehsankia]

Err, sorry, I mean't 0.5s, which is option A in Veratisium's video, and the time it actually takes for the current to go through the wire.