Does the light bulb light up at the moment of turning on the light, or does it light up after a while? Why?

We should be talking about incandescent lamps (hereinafter referred to as "bulbs"). First of all, about 90% of the electric energy generated by incandescent lamps is heat energy, and only about 65,438+00% of the electric energy emits light, so the filament is in a "cold state" at the moment of turning on the light, and does not emit light, and it can only emit light when it is heated to a certain temperature. The bulb power we usually say refers to the steady-state power of the filament after being heated and radiated. At the moment of turning on the light, the current is the largest when the filament is preheated, but the light is not on at this time. As we all know, the higher the temperature, the greater the resistance, so when the incandescent lamp is not turned on, its resistance is "cold resistance", which is much smaller than the resistance after the conversion of the nominal power of the incandescent lamp, but the heating of the filament is completed at the moment when the lamp is turned on, so the instantaneous impact power is often ignored when the nominal power is turned on. So technically, the higher the temperature, the brighter the light is right!