BPHCT-135 · December 2023 · English
IGNOU BPHCT-135 December 2023 Previous Year Question Paper
THERMAL PHYSICS AND STATISTICAL MECHANICS
Structured previous year question paper for BPHCT-135, December 2023 session.
Max marks: 50 · Questions: 6
Verified: 24 Aug 2026
BACHELOR OF SCIENCE (GENERAL)
(BSCG)
Term-End Examination
December, 2023
BPHCT-135 : THERMAL PHYSICS AND
STATISTICAL MECHANICS
Time : 2 Hours Maximum Marks : 50
Note :
(i) All questions are compulsory. However,
internal choices are given.
(ii) You can use a calculator.
(iii) Symbols have their usual meanings.
(iv) Marks for each question are indicated
against it.
Q1.Attempt any five parts : 2x5=10
(a) State any two assumptions of kinetic theory of gases.
(b) For dilute solutions, write Van’t Hoff expression for osmotic pressure and state its significance.
(c) Hot water flows into the radiator of a car and flows out after cooling by radiation of heat. Is it an example of an open or a closed system ? Justify your answer.
(d) State zeroth law of thermodynamics.
(e) A Carnot engine operates between 273 K and 77 K. Calculate its efficiency.
(f) Draw phase diagrams for COz.
(g) State the postulates of Planck for black body radiation.
(h) What do you understand by the term phase space ?
Q2.Answer any two parts:
(a) Discuss kinetic interpretation of temperature. 5
(b)
(i) State three assumptions of van der Waals used to derive his equation. 3 Gi) Plot vander Waals’ equation on indicator diagram. 2
(c) Describe Zartman and Ko experiment performed to verify Maxwell’s law.
Q3.Attempt any two parts:
(a) What is Brownian motion ? Discuss essentials of Einstein’s theory of Brownian motion. 243
(b) Differentiate between reversible and irreversible processes’ giving suitable examples. 5
(c) The density of a substance is p. Show that : 5 a 1/9 moi( Bh nto
Q4.Answer any two parts: 5x2=10
(a) 1 g water and steam occupy 1 cm® and 1671 cm’ at normal atmosphsic pressure. Calculate the change in the internal energy for vapourization of 1 g water at 100°C. Take latent heat of steam as 540 cal and mechanical equivalent of heat = 4.2 Jeal-!. p = 1.013 x 105 Nm, 5
(b) Using Maxwell’s relations, derive first and second energy equations. 5
(c)_ For two phases of a substance coexisting in equilibrium at constant temperature and pressure, obtain the Clausius-Clapeyron equation.
Q5.(i) Define spectral energy density of black- body radiation and emissivity of abody. 4 Gi) All oscillators vibrate with frequency
Q6.5 x 1014 Hz at 1800 K. Calculate their average energy. Considering them to be Planck’s oscillators. Take h = 6.62 x 10-%4 Js“ and kp = 1.38 « 10-8 JK. 6 The thermodynamic probability for a F-D system is given by : Wellin i! Obtain expression for F-D distribution function.