Thermodynamics (PHYS2140)
BSc, Physics - PHYS
Semester: First Semester
Level: 200
Year: 2016
THE UNIVERSITY OF BAMENDA
FACULTY OF SCIENCE DEPARTMENT OF PHYSICS
Thermodynamics: PHYS2140 Tutorial Sheet I
V
Continuous Assessment 2015/2016
Physics Year 1 Duration: 2h
Exercise 1
1. Represents the isotherms of van der Waals gases in the p-V diagrams
2. Write the van der Waals state equation, give the conditions of idealizing this state equation
3. Expand the product pv in Taylor serie with respect to v in the form
=
where A
and B should be determined.
Exercise 2: (5 marks)
The state equation of a real gas is written
(v - b) = RT, where R = 8.3J/mol.
o
K 5
41.4Pa.K.m
6
/molSI and b=3.3 x 10-5 m3/mol. The molar specific heat at constant volume is equal
to C =
R whatever the temperature when its pressure tends to zero
1) Calculate the value C
1
at temperature T, when the molar volume of gas is held to be v.
2) Calculate the variation AC
v
when the molar volume passes from v
0
to 3v
0
at constant
temperature. V0 = 30 litres / 300ok
Exercise 3: (3 marks)
The experiments have shown that the isobaric thermal expansion coefficient and the isothermal
compression coefficient of one mole of a gas is expressed in term of independent variables p and T. it
is written by the equations:
=
and
Where R and b are constants. Find the equation of state of this gas, relative to one mole.
Exercise 4: (7 marks)
One has one source of temperature T
A
. In relation with this source of heat, a monoatomic perfect gas
performs a cyclic process represented in the Clapeyron diagram. The cycle is composed of an adiabatic
process (AB), an isochore process (BC) and an isothermal process (C All these transformations
are considered as reversible. The initial state variables are pA, Va and T
A
. After the adiabatic process, V
b
= 2V
A
.
1) Determine the conditions (p.V.T) in B and C in terms of p
A
, V
A
and T
A
2) Find the expression of heat Q and work W of each process in the cycle in terms of P
A
, V
A
and T
A
3) Find the efficiency of the cycle
4) Find the change in internal energy !C and the entropy !" of each process
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