Heat and Thermodynamics

Thermodynamics is a branch of physics concerned with heat and temperature and their relation to energy and work. It defines macroscopic variables, such as internal energy, entropy, and pressure, that partly describe a body of matter or radiation.

Kinetic Energy = KE

                        = 1/2 mv²

Vebuity V = 0

mometntump = mv = 0

Heat is energy ------------------- energy = Joule

Heatis proportional of the KE of the modeculas of the suvstance.

Temperature is a number. If it exprssed in veluinon degree contorgoade.

Temperature is related of the average KE(Kelvin) of the molecles of the substance.

Thermocouple

The Voltage can be interpreted to measure temperature.

Zeroth law of thermolynamics

This is states zeroth law of Thermodynamics

First Law of Thermodynamics:

The first law of thermodynamics is the application of the conservation of the energy principle to heat and thermodynamic process.

The change in the internal energy of a system is equal to the heat added to the system minus the work done by the system.

The change in the internal energy of a system is equal to the heat added to the system minus the work done by the system.

first underline is for '<|U'

secound underline is for 'Q'

(-) for minus and last underline is for 'W'

<|U=Q-W

<|U = Change in internal system

Q = Heat added to the system

W = Work done by the system

Internal Energy

Internal energy is related to the kinetic energy and potential energy of the molecules of the substance.

W= pdv

Specific Heat

The specific heat is the amount of heat per unit mass required to raise the temperature by one degree celcias.
The relation between heat and temperature is usually expressed in the form shown below.

C=Q/m<|T , Were 'C' is the specific heat

Unit of C is = joule/gm^oc

Kainatic Enargy:-

KE = 1/2mv²

v = velocity

The relation does not apply if a phase change is encounterel, because the heat does not change the temperature.

Temperature is related to the average kinatic enargy.

1/1= infinati , Q/infinati = 0

C = Q/m<|T

C = Q/m x 0, where '<|T = 0'

C = Q/0

C = Infinati

Constant Volume specific Heat

Using 1^st law of thermodynamics

<|U = Q - W
       = Q                       [w=pdv=p<|v=0]
       = C_vn<|T
 C_v = <|U/n<|T .............................(I)

Cv = constant volume spacific hit

for monoatonic ideal gas:-

U = 3/2 nrT

<|U = 3/2 nr<|T .................. (2)

from (1) and (2)

Cv = 1/n<|T 3/2 nR<|T

Cv = 3/2 R

'r' = Monoatomic gas.

Constant Pressure Specific Heat

Cp = Cv + R       [Have to remember]

Cp = Cv + R
     = 3/2 R + R
     = 3/2 R + 2/2 R
     = 5/2 R