Thermal Physics Flashcards
What is heat?
Heat is thermal energy transferred from higher to lower temperature due to temperature difference
When will net transfer of thermal energy stop?
When both object reaches thermal equilibrium, eg. same temperature
When are two object in thermal equilibrium?
If they have same temperature and no net heat transfer between them
What is temperature?
- scalar base quantity that is proportional to the average KE of a substance
- a property that determines whether an object is in thermal equilibrium with other objects
Is temperature the measure of the amount of thermal energy in a body?
- no
- different heat capacity of object
- temperature shows direction of thermal energy transfer
What is the 0th law of thermodynamics?
If an object A and object B are separately in thermal equilibrium with a third object C, then A and B are in thermal equilibrium with each other
What is absolute scale?
thermodynamic temperature scale that does not depend on thermometric properties of any substance
What is absolute zero?
- Lowest limit of thermodynamic temperature scale
- a state at which the enthalpy and entropy change of a cooled ideal gas reach its minimum value, taken as zero kelvin
What is the triple point of water?
- temperature and pressure at which three phases (gas, liquid and solid) of that substance coexist in thermal equilibrium
- temperature and pressure at which sublimation curve, fusion curve and vapourisation curve meet
- 273.16K (0.01 degree celsius)
What is one kelvin?
1/273.16 of the thermodynamic temperature of the triple point of pure water
What is Boyle’s Law?
Pressure of a fixed mass of ideal gas at constant temperature is inversely proportional to its volume
What is Charles’ law?
Volume of a fixed mass of ideal gas at constant pressure is directly proportional to its thermodynamic temperature
What is pressure law?
Pressure of a fixed mass of ideal gas at constant volume is directly proportional to its thermodynamic temperature
What is ideal gas?
a gas which obeys pV=nRT, where p is the pressure of the gas, V is the volume of the gas, n is the total number of moles of gas, T is thermodynamic temperature of the gas
What are the assumptions for kinetic theory of gases and molecules?
- collisions between molecules and container are perfectly elastic
- molecules do not exert any intermolecular forces on one another
- time during collisions is negligible compared to time between collisions
- volume of molecules is negligble as comapred to volume occupied by the gas
- molecules are in rapid, random motion
- molecules of gas are hard, identical spheres
- average separation between molecules are large compared to size of molecules