A lightbulb has the power rated Pn=40W and the temperature of filament, during the functioning T=2200c degrees. How much power does the lightbulb
How much power does the lightbulb consume right off, during signing in, if the thermal coefficient of tungsten is A=4.5*10^-3 K^-1
Ro is the resistance of filament at 0C degree, then:
Po=U^2/[Ro(1+Atc)], where tc=the filament temperature at room temperature (t=20 C degrees)
We've noticed that the result is 10 times bigger than the rated power Pn=40 W, that's way lightbulbs are damaged when the light is turned on!