Thermal Physics Flashcards
What are the three laws of thermodynamics?
Zeroth law, Frist law, Second law
What is Zeroth law?
If A and B are in thermal equilibrium with C then A and B are in thermal equilibrium with each other
What is First law?
ΔE=Q-W (ΔE is net change in total energy, Q is heat added to the system, W is work doen by the system)
What is Second law?
In all spontaneous processes, the entropy of the universe increases i.e. entropy always increases with time
What is entropy?
The degree of disorder or randomness in a system
What is a system?
A portion of the Universe with certain measurable
quantities (such as pressure or volume) which determine the equilibrium state of
the system
What is an isolated system?
A system that does not interact with its surroundings by exchanging heat
energy, mechanical energy or material
What is a closed system?
A system in which energy but not material can be exchanged
What is am adiabatic wall?
The system is thermally isolated and
only mechanical energy (not heat) can be exchanged with the surroundings (e.g. a vacuum flask)
What is a diathermal wall?
Heat exchange is permitted; systems
connected by a diathermal wall are in thermal contact (e.g. a metal wall)
What does equilibrium mean?
All bulk physical properties are uniform throughout the system, they are time-independent
What does macroscopic mean?
Large-scale or bulk properties of a gas (e.g.: P, V, T)
What does microscopic mean?
Properties on the atomic-level (e.g.: vrms, vmp.)
What are state variables?
These define the state of a system
What does intensive mean?
Independent of the size of the system
Give 2 examples of intensive properties
pressure, tension
What does extensive mean?
Proportional to the size of the system
Give 2 examples of extensive properties
volume or length