A Light Emitting Diode (LED) is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with holes, releasing energy in the form of photons. As far as I know, an LED is not a blackbody.
In order to be a blackbody, an object must satisfy 2 conditions:
- It should absorb all em radiations that fall on it and be in thermal equilibrium.
- It should emit the maximum em radiation possible by a body of its mass.
I have four questions.
- Which of the conditions are not satisfied in the case of LEDs? Is high temperature a necessary condition for an object to be a blackbody?
- Does a burning incandescent lamp filament absorb all radiations that fall on it? If so, how do we know that?
- How is an incandescent lamp bulb filament in thermal equilibrium? (It seems to be way hot than its surroundings).
- Are all blackbodies hot objects? If an object is not hot does it automatically violate one of the above two conditions of a blackbody? I have seen people claiming that snow is a blackbody. How does that work?