Define Thermal equilibrium, Other Engineering

Assignment Help:
Thermal equilibrium
The definition and measurement of temperature must be logically preceded by the concept of thermal equilibrium and the Zeroth law. To determine operationally whether two systems are in thermal equilibrium, they are placed together in contact and isolated from the surroundings. If one of them is hot and the other cold then, after a certain period of time, the former feels less hot and the latter feels less cold. Simultaneously, changes in their physical properties, such as length, electrical resistance, etc. occur. After a sufficiently long time (equivalent to the relaxation time) no further changes take place. The two systems are then said to be in thermal equilibrium; they are said to have the same temperature.
Definition
Two systems are equal in temperature if no change in any physical property occurs when they are brought into communication. This definition must not be reversed. It does not imply that “when two systems are equal in temperature, no changes result from their communication”. For instance, if an electric lamp and a battery are connected by means of an electrical conductor, then the lamp will light up; this is, of course, a work interaction. Temperature is at the heart of the difference between work and heat; hence, the necessity to employ rigour in defining concepts relating to temperature. Two points are of significance with reference to the discussion on thermal equilibrium and equality of temperature:
• If the definition of temperature equality has to be given in such a manner as to apply equally well when it is reversed, the following condition should be added : “in the absence of any work interactions”.
• The process of “communication” indicated in the definition is in fact “thermal” communication (excluding any “work interactions”). But this usage leads to circularity and hence is not employed until after temperature equality is defined.

Related Discussions:- Define Thermal equilibrium

Tunnel diode, equivalent circuit of tunnel diode

equivalent circuit of tunnel diode

Aerodynamic centre, On a typical aerofoil, a point exists about which the r...

On a typical aerofoil, a point exists about which the resultant aerodynamic pitching moment M is independent of incidence. This special point is called the Aerodynamic Centre (AC).

Enhancing finance revenue.., Enhancing finance revenue In Corporate Fin...

Enhancing finance revenue In Corporate Finance and Business financial is the area of financial that promotion with financial options of organizations. Its main objective is to

What is tact?, What is Tact? Tact is nothing but a situational score ene...

What is Tact? Tact is nothing but a situational score energy. Once I had gone to a Govt workplace for getting documentation. There I was informed to provide unwanted fee more th

Measurement of thermocouple voltage, Measurement of thermocouple voltage ...

Measurement of thermocouple voltage The voltage is typically only a few millivolts and should be measured using a high impedance system. If an amplifier is used, must also have

Nozzle area and shape control, Nozzle Area and Shape Control In a high ...

Nozzle Area and Shape Control In a high by-pass ratio engine with a single-stage fan without inlet guide vanes, the predominant sources governing the overall noise level are th

thermoelectric effect, Thermoelectric effect The measurement of temper...

Thermoelectric effect The measurement of temperature using a thermocouple relies on Seebeck effect. The electrons occupy different energy levels in different materials

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd