There has been a lot of interesting discussion about light bulbs. But,
no one seems interested in the overall change in resistance that must
occur -- or, perhaps I missed it.
I measured the (cold) resistance of a 60W bulb at approx. 19.4 ohms.
But, in operation (at 117 volts), the resistance will be approx. 230
ohms. This leads to a look at the temperature coefficient of
resistivity, which is poorly handled (it is not linear) in most lower
level textbooks.