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SET-1

Andhra 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- B

Part 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)      Differentiate
between isothermal and adiabatic processes.

2)      What
are T-S diagram? What are the uses of them?

3)       Explain any two applications of Clausius -
Clapeyron equation.

4)       State law of equipartition of energy?

5)      Define mean free path and write its
equation.

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)  In an adiabatic process, the temperature of one mole of
an ideal monatomic gas (g=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)

13)  Calculate
the change in entropy when 1 kg. of ice at 0^oC is converted into
water at 0^oC. Latent heat of fusion of ice = 3.34 x 10⁵
J/K.

14)  Sodium
light of wavelength 5890 A^o 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 10^th 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 n^th bright and dark rings.
   ( 16 marks)

**** 

Andhra Loyola College (Autonomous) :: Vijayawada-8

II B.Sc - IV
Semester- Physics- Paper IV

(Thermodynamics
& Optics)

Time  : 3 hours                                                                          Max
marks : 100

-----------------------------------------------------------------------------------------------------------

NOTE:

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- B

Part 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 of the following                                                        
10 x 2 = 20 marks

 

1)      Write
any two properties of thermal radiation.

2)      What
are merits of radiation pyrometers?

3)      Write
the principle of adiabatic demagnetization.

4)      Write
any two properties of a refrigerant.

5)      Explain the concept of phase space in brief.

6)      State
any 2 difference between a convex lens and a zone plate.

7)      Define
dispersive power of a grating

8)      State
any 2 difference between Fresnel and Fraunhofer
diffraction

9)      State
and explain Brewster’s Law.

10)    What do you mean by half wave plate?

11)  Calculate
the energy of a classical oscillator at 127 ^oC (Boltzmann constant
is 1.38 x 10^-23 JK^-1.

12)  Van
der Waal’s constants a and b for one mole of a gas are 0.2 atm-litre²
mol^-2 and 0.03 litre/mol respectively. Calculate the temperature of
inversion (Universal gas constant is 8.31 J mol^-1 K^-1).

13) 
Find the ratio of the temperatures of two black
bodies which emit radiations of maximum energy at wavelengths 4800 Å and 5400 Å
respectively.

14)  Find
the radius of the hundredth circle on a zone plate behaving like a convex lens
of focal length 50 cm.

15)  A
ray of light is incident on the surface of benzene of refractive index 1.5. If
the reflected light is linearly polarized, calculate the angle of reflection.

           

                                   

Part – B

Answer all                                                                                                       5
x 16 = 80 marks

16. a)  State Wien’s
displacement law.                                                              (
3 marks)

      b) Derive Wien’s displacement law.                
                                                      ( 13 marks)

(OR)

c) What is Planck’s
hypothesis?                                                                               (
3 marks)

d) Derive Planck’s radiation formula.                                                                        (13
marks)

17. a)  Describe
Joule-Thomson porous Plug experiment.                                              (13
 marks)

      b)  What are the important inferences from this
experiment?                         (3
marks)

(OR)

     c) What
is Joule-Thomson effect?                                                                            (3 marks)

     d) Derive an expression for Joule-Thomson cooling.
                                                (13
marks)

18. a) Express Bose-Einstein law mathematically.                                                          (3
marks)

       b)
Apply Bose-Einstein statistics to a photon gas.                                       (13 marks)

   

                                                            (OR)

c)   With
necessary mathematical theory, explain the intensity pattern due to diffraction


       at straight edge according to
Fresnel’s theory of diffraction.            ( 16  marks)

19. a) Describe
the Fraunhofer single slit experiment and explain the intensity distribution

       curves due to a single slit.                                                                            ( 16 marks)

(OR)

b)     
Describe the Fraunhofer diffraction pattern
of a plane grating for normal incidence and explain its intensity distribution.                              
                       ( 16 marks)

20. 
 a)   
What is double refraction ? Describe Huygen’s theory of double
refraction in

               uniaxial crystals.                                                                                             (
12 marks)

b)
State and explain Brewster’s law                                                                  (4
marks)

(OR)

c) 
Write a note on Babinet’s compensator.                                                 (  8 marks)

d)  
What do you mean by Optical activity ? Explain about dextro and laevo
rotatory

        crystals.                                                                                                          (
8 marks)

     

***