I have a bulb which is hot enough to emit visible light and obviously it's hot enough to emit radiation which lies before the visible light temperature i.e. radio waves, microwaves, and infrared light. So is the bulb emitting radio waves, microwaves, infrared and visible light at the same time?
(I think this is true but not sure as astronomers see stars at almost all light i.e. infrared, UV, Gamma rays, visible etc.)
Thanks in advance!
Best Answer
For light bulbs and other thermal emitters this is definitely true. Their emission follows the black body spectrum (if you neglect absorption due to the glass container).
If you want to be picky: Any device, which is operated above 0 K (which applies to all devices) emit thermal radiation according to their temperature. This is not directly related with the light generation in e.g. solid-state, semiconductor or gas lasers. Any electrical or optical loss mechanism results in heat generation, which results in some thermal radiation. Yet for my understanding, this is not directly, what was asked for in the first paragraph.