II B.Sc., - PHYSICS – III SEMESTER –PAPER –III(THERMODYNAMICS &OPTICS)

SYLLABUS-Credits :4

PART A: THERMODYNAMICSUNIT I: Laws of Thermodynamics: (12 Periods)

(a) Heat and Work - Internal Energy - Indicator diagram - work done in isothermal and

adiabatic processes First law of thermodynamics - significance and applications of first law

of thermodynamics - Reversible and Irreversible process - Carnot’s engine and efficiency-

Carnot’s theorem.

(b) Second law of thermodynamics - different statements - Thermodynamic Scale of

temperature

UNIT II:Entropy and Thermodynamical potentials: (12 Periods)

a) Entropy Concept - Entropy of steam - Change in reversible and irreversible processes -

Entropy-Temperature Diagrams.

b) Thermodynamic Potentials - Derivation of Maxwell’s Thermodynamic relations - Clausius

- Clapeyron equation Specific heat – derivation of ratio and difference of two specific heats -

Joule-Kelvin effect - Expression of Joule- Kelvin Coefficients.

UNIT III : (12 periods)

a) Kinetic Theory of Gases : Postulates of Kinetic theory of gases - Law of equipartition of energy - Derivation of

Maxwell’s law of distribution of molecular speeds -Mean free path (brief explanation),

Transport phenomena - viscosity and thermal conduction.

b) LASERS &Fiber optics:

Spontaneous and Stimulated emissions- laser principle - Population inversion – Active

substance –Ruby laser. Holography, principle and applications. Introduction to Fiber optics-

Principle, types, single step and graded index fibers and their structure-fiber materials

UNIT IV: (12 periods)

a) Matrix Methods in Paraxial Optics:                                          

Concept and derivation of translation, refraction and system matrices - Position of the image

plane and magnification of the optical system - Application of matrix method to simple

optical systems – (i) Thick lens (ii) Two thin lenses in contact (iii) Two thin lenses separated

by distance - Cardinal points of a lens system - unit and nodal planes (brief explanation only).

b) Introduction to Interference by division of wavefront:

Principle of superposition - Coherence - Conditions of Interference of light.- Young’s

double slit experiment – Expression for band width. Fresnel’s Biprism – determination of

wavelength of light . Determination of thickness of a transparent material using

displacement of fringes. Change of phase on reflection – Stoke’s law- Lloyds mirror –

Experimental determination of wavelength of light.

Unit V: Interference by division of wavefront & amplitude: (12 Periods)

Oblique incidence of a plane wave on a plane parallel thin film - Cosine law – plane parallel

thin film- Colours of thin films – Non-reflecting films - Newton’s rings in reflected light -

Determination of Wavelength of monochromatic light- Newton’s rings in transmitted light

(Brief)- Michelson’s Interferometer- Determination of wavelength of monochromatic light,

thickness of a thin Plate.

Reference Books:

1. Unified Physics - Thermodynamics & optics Vol. -2- Dr. S.L. Gupta & Sanjeev Gupta

2. Optics - Brijlal and Surahmanyam (S.Chand & Co)

3. Fourier Optics - Good Man

4. Fiber Optic Communications - Agrawal, Ped wheeler pub,

5. B.Sc. Optics - Telugu Academy

6. B.Sc. Heat - Telugu Academy

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MODEL QUESTION PAPERAndhra Loyola College (Autonomous) :: Vijayawada-8

II B.Sc - III Semester- Physics- Paper III(Thermodynamics & Optics)

Time : 3 hours Max marks : 100 -----------------------------------------------------------------------------------------------------------

Part – A

Part A consists of 15 questions with the composition as very short answer type questions (10) and problems (5).

There will be 3 questions from each unit out of which 10 are to be answered (10 x 2 = 20 marks).

The very short answer type questions may be asked to test the knowledge of the subject.

Part- BPart B consists of 5 questions (with internal Choice) from each unit (5 x 16 marks = 80). The questions may be of essay type. However, short answer type questions may also be asked as sub questions, depending on the length of the essay to be answered.

Part – A (Answer any 10) 10 x 2 = 20 marks

1) In an adiabatic process, the temperature of one mole of an ideal monatomic gas (=5/3) is decreased from 500 K to 300 K. What is the work done during the process? (Universal Gas Constant =8.314 J mol-1

K-1)2) Differentiate between isothermal and adiabatic processes. 3) What are T-S diagram? What are the uses of them?4) Explain any two applications of Clausius - Clapeyron equation.5) State law of equipartition of energy?6) State any 4 applications of Holography.7) What the matrices that represent Translation and Refraction?8) Describe the structure of Fresnel’s Biprism. 9) State and explain Stokes law?10) What are non reflecting films?11) Determine the efficiency of a Carnot engine working between 2270 C and 270 C.12) Calculate the change in entropy when 1 kg. of ice at 0oC is converted into water at

0oC. Latent heat of fusion of ice = 3.34 x 105 J/K.13) Define mean free path and write its equation. 14) Sodium light of wavelength 5890 Ao passes through two narrow slits 2 x 10-3 m apart.

The interference pattern is seen at a distance of 1.25 m away from the centre of the slits. Determine the fringe width.

15) In Newton’s ring experiment, the diameter of the 10th dark ring is 0.433 cm. Find the wavelength of incident light, if the radius of curvature of the lens is 70 cm.

Part – B (Answer all) 5 x 16 = 80 marks

1. a) Describe the working of Carnot’s heat engine and derive an expression for its efficiency. ( 16 marks)

(OR)b) State and explain second law of thermodynamics ( 6 marks)c) What is absolute Scale of temperature? Define absolute zero in the scale. ( 10 marks)

2. a) What is entropy? Obtain an expression for the change in entropy for a reversible process. (8 marks) b) Obtain an expression for the entropy of steam (8 marks)

(OR) c) What are thermodynamical potentials? Obtain Maxwell’s thermodynamical relations from thermodynamical potentials ( 16 marks)

3. a) Derive Maxwell’s law of distribution of molecular speeds. (16 marks)

(OR)b) Write a note on spontaneous emission and stimulated emission. ( 6 marks)c) What are step index and graded index fibers. Explain their structure. ( 10

marks)

4. a) Obtain the system matrix for a thick lens. Derive the formula for the focal length of the thin lens as well as thick lens. ( 16 marks)

(OR)b) Describe Young’s double slit experiment. Derive the expression for band width.

( 16 marks)

5. a) Obtain Cosine law in reflected light. ( 12 marks) b) How are colours formed on thin films? ( 4 marks)

(OR)c) Describe the experimental arrangement to observe Newton’s rings by reflected light.

Obtain an expression for the diameters of nth bright and dark rings. ( 12 marks)d) State and prove Stokes law for reflection of light in a denser medium ( 4 marks)

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