Quick Recap of Thermodynamics

Notes for Examination


Temperature

Relation between Celsius and fahrenhite scale is

TF=9/5 TC + 32°

TF - Fahrenhite Temperature
TC - Celsius Temperature

Relation between Celsius and kelvin scale is
TC = TK - 273.15 K


TK - Temperature in Kelvin
TC - Temperature in celsius


- If R0 & R100 are resistance of metak wire at ice and steam point resp then temp t can be defined corresponding to resistance RT as follows



T = (RT-R0)*100
R100-R0





- The pressure,volume and temperature in kelvin of such gases obey the equation
PV=nRT ----(1)



Thermal expansion

ΔL=αLΔT


Specific Heat Capacity



c = `Q
nΔT


Gas Laws
Boyles Law: PV=constant
Charles Law : V/T=constant
Dalton Law of Partial Pressure: P=P1 + P2 +P3
Root mean Square Velocity
Vrms=√3RT/M
Mean Square Velocity
Vm=√8RT/&#960M
Average Velocity
V=√2RT/M
Also
Vrms > Vm > V

Average kinetic Energy of Gas=3/2nRT


First law of Thermodynamics

ΔU=Q-W


Gas Processes

Isothermal Process : PV=constant ,ΔU=0,Q=W,Molar Specific Heat=infinity
Adaibatic Process : PVy=constant,Q=0,ΔU=-W,Molar Specific Heat=zero
Polytropic Process : PVn=constant,Molar Specific Heat=R/y-1 + R/1-n
Volume Constant : P/T=constant W=0,ΔU=Q,Molar Specific Heat=Cv
Pressure Constant : V/T=constant ΔU=Q-W ,Molar Specific Heat=CP

Internal energy depends on Temperature.
So for same temperature change ΔT
nCvΔT=Q1-W1=Q2-W2=Q3-W3

Molar Specfic Heat Capacity of any process is given by

C=Cv + Pdv/ndT where n is no of moles of the gas

Workdone by Gas= ∫PdV



Heat Conduction

Q=-KAdT/dx

Wein displacement lawλT4=Constant

Stefan's Law
Q=eσT4

Newton law of Cooling

dT/dx=b(T-Ts)










T =

(RT-R0)*100

R100-R0
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