[hamdani yusuf (OP)]

The question is, which object is the hottest?

The electrons in the LED with an energy of a few electron volts, corresponding to a temperature of tens of thousands of kelvin.

Does it melt?

How the F*** do you expect an electron to melt?

How could you think that it referred to electron instead of LED?

[alancalverd]

How do you think LEDs work? Magic or electrons?

[Bored chemist]

How could you think that it referred to electron instead of LED?

Because it's totally obvious to anyone that the LED doesn't melt.

[hamdani yusuf (OP)]

How could you think that it referred to electron instead of LED?

Because it's totally obvious to anyone that the LED doesn't melt.

What's the temperature of the LED?
Why it's different from the temperature of the electrons?

[alancalverd]

Most LEDs work in the range 250 -  350K, with efficiency decreasing outside that range.

The working temperature of the chip represents the kinetic energy of the nuclei, which account for most of the mass of the substrate material and hence most of the thermal energy of the LED itself. The heat sink and casing are (or should be) in near-equilibrium with the substrate.

Within the chip, the active electrons responsible for light emission obviously have mean energies of the order of visible photons, 2 - 4 eV.    1 eV  ≈ 11,605 K

[Bored chemist]

How could you think that it referred to electron instead of LED?

Because it's totally obvious to anyone that the LED doesn't melt.

What's the temperature of the LED?
Why it's different from the temperature of the electrons?

FFS!
How many times?
The electrons do not, in this instance, have a well defined temperature.

[hamdani yusuf (OP)]

The electrons do not, in this instance, have a well defined temperature.

Then why did you write this statement?

The electrons in the LED with an energy of a few electron volts, corresponding to a temperature of tens of thousands of kelvin.

[hamdani yusuf (OP)]

Within the chip, the active electrons responsible for light emission obviously have mean energies of the order of visible photons, 2 - 4 eV.    1 eV  ≈ 11,605 K

Why don't they cause the LED to melt down?

[alancalverd]

Because the kinetic energy transfer between an electron and a nucleus is very weak.

A poor analogy: collect the sparks from a grinding wheel in a bucket of water. The sparks are at about 800 - 1000 K but you won't get the water to boil.

[Bored chemist]

The electrons do not, in this instance, have a well defined temperature.

Then why did you write this statement?

The electrons in the LED with an energy of a few electron volts, corresponding to a temperature of tens of thousands of kelvin.

To remind you that not all energy is temperature.

Did you not notice that I said the energy corresponded to a temperature, not that the electrons were at that temperature?

[Bored chemist]

Within the chip, the active electrons responsible for light emission obviously have mean energies of the order of visible photons, 2 - 4 eV.    1 eV  ≈ 11,605 K

Why don't they cause the LED to melt down?

Because someone has cleverly arranged things so that it's more likely that they will lose that energy by emitting light than that they will transfer it to thermal energy,

[hamdani yusuf (OP)]

Did you not notice that I said the energy corresponded to a temperature, not that the electrons were at that temperature?

How are they correlated?
Is it proportionally? Or inversely proportional? Or another type of correlation?

[hamdani yusuf (OP)]

Within the chip, the active electrons responsible for light emission obviously have mean energies of the order of visible photons, 2 - 4 eV.    1 eV  ≈ 11,605 K

Why don't they cause the LED to melt down?

Because someone has cleverly arranged things so that it's more likely that they will lose that energy by emitting light than that they will transfer it to thermal energy,

How is it done?

[alancalverd]

Try

https://electronics.howstuffworks.com/led.htm

[hamdani yusuf (OP)]

Try

https://electronics.howstuffworks.com/led.htm

LEDs generate very little heat, relatively speaking. A much higher percentage of the electrical energy is going directly to generating light, which cuts down the electricity demands considerably.

But when the light produced by LED hit the paper, it burns.
In the video, there is a segment where the light is reflected back to LED using a mirror. The LED breakdown as a result.

[Bored chemist]

Did you not notice that I said the energy corresponded to a temperature, not that the electrons were at that temperature?

How are they correlated?
Is it proportionally? Or inversely proportional? Or another type of correlation?

I'm sure I already told you about the equipartition principle.
https://en.wikipedia.org/wiki/Equipartition_theorem
Try reading it again.
Maybe take notes if that helps you remember stuff.

[Bored chemist]

Within the chip, the active electrons responsible for light emission obviously have mean energies of the order of visible photons, 2 - 4 eV.    1 eV  ≈ 11,605 K

Why don't they cause the LED to melt down?

Because someone has cleverly arranged things so that it's more likely that they will lose that energy by emitting light than that they will transfer it to thermal energy,

How is it done?

That's really not a subject that is suitable for a discussion site. It's a lot of technical information.
Are you able to use a search engine and ask how LEDs are made?
(Don't use AI; they produce dross)

[Bored chemist]

But when the light produced by LED hit the paper, it burns.

Why would it not?

[alancalverd]

But when the light produced by LED hit the paper, it burns.
In the video, there is a segment where the light is reflected back to LED using a mirror. The LED breakdown as a result.

What do you expect? Photons deliver energy to the absorber.

[hamdani yusuf (OP)]

But when the light produced by LED hit the paper, it burns.
In the video, there is a segment where the light is reflected back to LED using a mirror. The LED breakdown as a result.

What do you expect? Photons deliver energy to the absorber.

The question is, why the materials in the LED didn't absorb the light during the emission, but did absorb the light after reflection by the mirror?