Two systems are in mutual thermal equilibrium if the state variables of neither change when the two are placed in thermal contact Two initially isolated systems not in mutual thermal equilibrium are placed in thermal contact they eventually achieve mutual thermal equilibrium ID: 759237
Download Presentation The PPT/PDF document "1 You will learn 2 Concept of thermal eq..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
1
You will learn
Slide22
Concept of thermal equilibrium is unique to the science of thermodynamics.Two systems are in mutual thermal equilibrium if the state variables of neither change when the two are placed in thermal contact.Two initially isolated systems, not in mutual thermal equilibrium, are placed in thermal contact, they eventually achieve mutual thermal equilibrium.
Thermal Equilibrium
Slide3Observed that a higher temperature object which is in contact with a lower temperature object will transfer heat to the lower temperature object. Objects will approach the same temperature, and in the absence of loss to other objects.Maintain a constant temperature.
3
Thermal Equilibrium
Thermal Equilibrium
Cooling a hot object
Cooling with ice
Cooling by evaporation
Calorimetry
Cooling of
cup of coffee: Example
Slide4Two systems are at the same time in thermal equilibrium with a third system, they are in thermal equilibrium with each other.If A and C are in thermal equilibrium with B, then A is in thermal equilibrium with B. Three are at the same temperature, and it forms the basis for comparison of temperatures.
4
Zeroth Law of Thermodynamics
Slide55
Allows us to specify a single thermodynamic system as an indicator of thermal equilibrium.Thermometer state variables do change – two systems are not in thermal equilibrium.
Zeroth Law of Thermodynamics
Slide66
Based on easily reproducible states: freezing and boiling points of water.Temperature scale that is independent of the properties of any substance - thermodynamic temperature scale.Which is developed in conjunction with the second law of thermodynamics.Turns out to be identical to the Kelvin scale - ideal gas temperature scale.Measured using a constant-volume gas thermometer, which is basically a rigid vessel filled with a gas, usually hydrogen or helium.
Temperature Scales
Slide7Thermometer is based on the principle that at low pressure.Temperature of the gas is proportional to its pressure at constant volume. Relationship between the temperature and the pressure of the gas in the vessel, . Where a , b are constant.
7
Temperature Scales