# Measurement of heat in electrons

Is there any method to measure the heat of an electron and if there is; then is it a constant or a variable.

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do you mean temperature or something other –  agha rehan abbas Jun 28 '14 at 18:19
no the amount of energy converted into heat which in turn changes the temperature of an object. –  Sahmiran Jun 30 '14 at 8:39

## 2 Answers

Heat is a thermodynamic quantity defined in the framework of thermodynamics.

Heat, in the strict use in physics, is characteristic only of a process, i.e. it is absorbed or produced as an energy exchange, always as a result of a temperature difference. Heat is thermal energy in the process of transfer or conversion across a boundary of one region of matter to another, as a result of a temperature difference.2 In engineering, the terms "heat" and "heat transfer" are thus used nearly interchangeably, since heat is always understood to be in the process of transfer. The energy transferred by heat is called by other terms (such as thermal energy or latent energy) when this energy is no longer in net transfer, and has become static.3 Thus, heat is not a static property of matter. Matter does not contain heat, but rather thermal energy, and even the thermal energy is subject to transformations into and out of other types of energy, and so can be considered to be "conserved" only when these processes are small. The heat transfer rate or heating rate is the amount of energy per unit time being transferred as heat, or the heat power.

Thermodynamics is about bulk matter which is composed of ~10^23 molecules per mole.

A glass of water can have a heat content, can be hot, characterized by its temperature, but it is not good usage to say it has heat. More so of the single elementary particle which is the electron. It is a point particle and does not have a multitude of internal degrees of freedom that a glass of water has.

It does have energy , even when it is at rest , because of special relativity, its mass of about 0.5 MeV is in energy units. If in motion the energy increases.

An ensemble of electrons can behave thermodynamically and have a heat content and be characterized by a temperature. In statistical mechanics the temperature is connected with the average kinetic energy of the components of the gas.

E_K the average kinetic energy, v the velocity, rms ="root mean square", T the temperature, k the Bolzmann constant

When one has a single electron of energy E, by a stretch of the matter one can assign a temperature as if that E were the average kinetic energy of a gas of electrons, but it is just an analogy.

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I am wondering if one could properly define the temperature of conducting electrons by noting the equivalent noise temperature of a semiconductor amplifier at least in the majority carrier case, such as FETs (not BJTs). For example, if the noise figure were say 2(3dB) then that would imply that the equivalent temperature is just the ambient reference temperature, $$NF = 1+\frac {T_{eq}}{T_{amb}}$$.

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