Thermodynamics (PHYS2140)
BSc, Physics - PHYS
Semester: First Semester
Level: 200
Year: 2016
THE UNIVERSITY OF BAMENDA FACULTY OF SCIENCE
DEPARTMENT OF PHYSICS
Continuous Assessment, 2015/2016
Thermodynamics: PHYS2140 Physics year 1 Duration: 2h
Exercise 1: (5 marks)
1. Represent the isotherms of van der Waals gases in the P-V diagram
2. Write the van der Waals state equation, give the conditions of idealizing this state equation
3. Expand the product in Taylor series with respect to in the form
.
Where A and B should be determined.
Exercise 2: (5 marks)
The state equation of a real gas is written
, where ! "
##$" ! SI and % &
'(
)
The molar specific heat at constant volume is
equal to *
(
+
whatever the temperature when its pressure tends to zero.
1. Calculate the value of *
at temperature , when the molar volume of gas is held to be .
2. Calculate the variation ,*
, when the molar volume passes from
-
to
-
at constant
temperature,
-
.&/01234 && !
Exercise 3 (3 marks)
The experiments have shown that, the isobaric thermal expansion coefficient 5 and the isothermal
compression coefficient 6 of one mole of a gas, is express in term of independent variables and ,
it is written by the equation: 5
78
and 6
78
where 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
. In relation with source of heat, a monoatomic perfect gas
performs a cyclic process represented in the Clapeyron diagram. The cycle is composed of an
adiabatic process 9 : ;, an isochoric process ; : * and an isothermal process * : 9. All
these transformation are considered as reversible. The initial state variables are
4<
and
. After
the adiabatic process, <
.<
.
1. Determine the conditions 4<4 in B and C in terms of
4<
and
2. Find the expression of heat = and work W of each process in the cycle in terms of
4<
and
.
3. Find the efficiency of the cycle >
?
@
?
A
.
4. Find the change in internal energy ,B and in entropy ,C of each process.
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