# Shared Flashcard Set

## Details

PHYS 213
UIUC PHYS 213 SP 2018 Review
56
Physics
04/04/2018

Term
 pressure is (SI units, formula)
Definition
 pressure = Force/AreaSI units of Pascals
Term
 Largest entropy of sum of two dice
Definition
 7Possible states of (1,6),(2,5),(3,4),(4,3),(5,2),(6,1)
Term
 Net work using pressure and volume
Definition
 [image]
Term
 Say you want to find the number of microstates in a box of volume V and no of particles N. How would I do that?
Definition
 [image]
Term
 Box of N particles split into two bits. Find information about the equilibrium.
Definition
 [image]
Term
 Delta S given Vi Vf and N
Definition
 [image]
Term
 Given a graph of S and U, how do I find T. Which S vs U graph is impossible?
Definition
 dS/dU = 1/TdS/dU > 0 because T > 0
Term
 Given Q and T graph how to find C
Definition
 C = dQ/dT
Term
 Find delta S given C Tf and Ti
Definition
 [image]
Term
 Difference between c_p and c_v
Definition
 8.31 usually (esp for noble gas)
Term
 Transnational KE and properties
Definition
 [image]*Independent of Mass*avg KE per atom
Term
 DOF for water molecule (not straight)
Definition
 3 transnational 3 rotational = 6
Term
 Avg speed of molecule
Definition
 [image]
Term
 What type of molecule would have the largest c_v
Definition
 One with lots of bonds, tons of DOF.
Term
 U for solids (DOF for solids)
Definition
 U = 3NkTDOF = 6c_p for solids is also just 3R
Term
 Give the difference between C_v c_v and C_v,mol
Definition
 C_v is the total heat capacity of a substanceExample Cv of 50 mol He is 629 J/kc_v is the specific heat (heat capacity per unit mass)c_v for helium is 3120 J/kgKc_v,mol is the heat capacity per mole.Dependent on DOF - c_vmol for He is 12.5 J/molK
Term
 c_pmol - c_vmol
Definition
 8.31 = R
Term
 Total no of microstates of quantum oscillatorU in quantum oscillator
Definition
 [image]U = qhf
Term
 I know C(T). What can I do from here?
Definition
 [image][image]
Term
 I know U(T). What can I do? Also, where would I usually get U(T) from?
Definition
 [image][image]Get U(T) from equipartition:U9T) = Ndof/2 *kT + CBoltzmann gives U(T) also.
Term
 Know S vs U (S(U)). What can I do? Where do I usually get S(U)?
Definition
 Find U(T) using:[image]Get S(U) from counting states.S(U) = kln(states)(U)Can use U(T) to find C[image]
Term
 when is dS/dU = 1/T valid? How about C = dU/dT
Definition
 1) equilibrium2) constant volume
Term
 What happens to S of a 2 state system at T->0? How about T -> infinity?
Definition
 1) S -> 0 because there is only one state available.2) Each state is just as likely. kln(states) = kln2 usually.
Term
 Average total energy of a state in a quantum oscillator
Definition
 = Probability of state * Energy of state = P*ETotal avg energy in 2 state:U = E_H P_H + E_L P_LCan find C from dU/dTGeneral formula:[image]
Term
 Boltzmann Atmosphere
Definition
 U = mghCan use this to see how much particles in the atmosphere fall off by. Show that you can use anything for U, not just a random energy given.
Term
 Macrostate vs microstate
Definition
 Macrostate - Things like U,V,NMicrostate - position and velocity
Term
 Adding heat to something at a constant temperature. What's delta S
Definition
 [image]
Term
 Solve two blocks coming to equilibrium
Definition
 [image]Do that for BOTH blocks, and then:[image]
Term
 Carnot Engine (properties)
Definition
 Most efficient:[image]Delta S > 0[image]
Term
 Carnot Engine (efficiency)
Definition
 [image]
Term
 How to use pV diagrams?
Definition
 [image]Integrate the segments. <- means negative work_by -> means positive work by
Term
 Which processes are reversible?
Definition
 Isothermal and adiabatic are reversibleIsochoric and Isobaric are irreversible.
Term
 What's zero in a reversible process?
Definition
 *Change in total energy!!*Change in total entropy
Term
 What is the relationship between quasi-static processes and reversible processes?
Definition
 All reversible processes are quasi-static.NOT True:All quasi-static are reversible
Term
 COP for Fridge and Heat Pump
Definition
 [image][image]
Term
 General Engine Efficiency
Definition
 [image]
Term
 Stirling Engine property
Definition
 [image]
Term
 Free Energy of a System
Definition
 [image]Example of brick in a room[image]
Term
 How to calculate max work from brick?
Definition
 [image]where:[image][image]
Term
 Free Energy - Capacitor
Definition
 [image]
Term
 Modified ordering of isoX.
Definition
 1) Isobaric2) Isothermal3) Adiabatic4) IsochoricThis will be used for everything else.
Term
 What part of PV is constant for each of the elements
Definition
Term
 What are the "cutoffs" for:DeltaT, deltaUWbyQindeltaS
Definition
 1) zero at 2, decreases down2) zero at 4, decreases down3) zero at 3, decreases down4) zero at 3, decreases down
Term
 How much does entropy change during a phase change
Definition
 [image]
Term
 How do chemical potentials of the 2 phases compare during a phase change?
Definition
 They are equal!
Term
 What's zero during a phase change?
Definition
 delta G
Term
 What's G at constant T and P?
Definition
 [image]
Term
 Whats du/dT at constant pressure and N
Definition
 [image]
Term
 U in "Thermo of Photons"
Definition
 U = AVT^4
Term
 pressure in "thermo of photons"
Definition
 p = U/3V = (AT^4)/3
Term
 Other variables (ex: C_v) in thermodynamics of photons
Definition
 Same relationships still apply, acts like a normal system. Example:C_v = dU/dT = 4AVT^3
Term
 S in thermodynamics of photons
Definition
 S = 4U/3T
Term
 What star is the hottest?
Definition
 One that emits:lowest wavelengthhighest frequency
Term
 Wavelength -> highest (700nm) to lowest (400nm)
Definition
 ROYGBIV (Red - 700, Violet - 400)
Term
 [image] in thermal radiation (definition)Total power from a star
Definition
 Power/surface areaPower = J*A = A([image])(T^4)
Term
 Why isn't the same amount of energy reflected back to Earth as is reflected out to space?
Definition
 The Earth emits photons at a different frequency than the sun.
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