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Tuesday, October 16, 2012

First/Second Semester B.E. Degree Examination, January 2013-Model Question Paper












USN                                                                     10PHY12/22                                                                                                 

First/Second Semester B.E. Degree Examination, January 2013
Engineering Physics
Time: 3 hrs.                                                                                                                 Max. Marks:100

Note: 1. Answer any FIVE full questions, choosing atleast two from each part.
          2. Answer all objective type questions only in OMR sheet page 5 of the answer booklet.
          3. Answer to objective type questions on sheets other than OMR will not be valued.
          4. Physical constants: h = 6.626×10-34 Js, c = 3×108 m/s, me = 9.1×10-31 kg,
                                             k = 1.38×10-23 J/K, ε0 = 8.854×10-12 F/m

PART-A
1 a.  i) Electrons behaves as a wave because they can be
          A) Diffracted by a crystal                     B) Deflected by magnetic field                                 
          C) Deflected by electric field               D) Ionise a gas
       ii) In a blackbody radiation spectrum, the Wien’s distribution law is applicable only for
A) Longer wavelength   B) Shorter wavelength   C) Entire wavelength     D) None of these
       ii) If the momentum of a particle is increased to four times, the de-Broglie wavelength is
           A) become twice          B) become for times          C) become one-fourth           D) become half
       iv) If the group velocity of a particle is 3×106 m/s, its phase velocity is
          A) 100 m/s          B) 3×106 m/s             C) 3×108 m/s                  D) 3×1010 m/s           (04 marks)
   b. Describe Davisson-Germer experiment to prove the dual nature of matter waves.        (06marks)
   c. Derive de-Broglie wavelength using Group velocity.                                                      (06 marks)
d. Compare the energy of a photon with that of a neutron when both are associated with wavelength of 1 Å. Given that mass of neutron is 1.678 × 10 -27 kg.                                                       (04 marks)

2 a. i) According to Max Born approximation, |y|2 represents    
      A) Energy density          B) Particle density         C) Probability density          D) Charge density
     ii) The wavefunction is acceptable if it is
        A) Finite everywhere                                           B) Continuous everywhere  
        C) Single valued everywhere                               D) All of these            
    iii) The first permitted energy level is called
      A) Excited energy level   B) Zero point energy               C) Ground level         D) None of these
    iv) The wavefunction for the motion of particles in one dimensional potential box of length ‘a’ is given by yn = D sin npx/a where ‘D’ is normalization constant. The value of ‘D’ is
        A)                                 B)                          C) a                        D)                                                                                                                                                                       (04 Marks)
b. Set up time independent one dimensional Schrödinger wave equation.   (06 Marks)                  
c. What is a wave function? Explain the properties of a wave function.            (04 Marks)
d. A quantum particle confined to one dimensional box of width ‘a’ is in its first excited state. What is the probability of finding the particle over an interval of (  marked symmetrically at the centre of box.                                                                                                                                     (06 marks)


3 a. i) The classical value of molar specific heat of a conductor is
A) 3/2 R            B) ½ R                        C) 3R              D) 5/2 R
      ii) For ordinary metals, the resistivity versus temperature curve at T = 0,
A) has a positive intercept                              B) has a negative intercept
C) goes through the origin                              D) none of these
     iii) Ohms law relates to the electric field E, conductivity s and current density J as
A) J = E/s       B) J = sE2        C) J = s/E      D) J = sE
    iv) If the Fermi energy of silver is 5.5 eV, the Fermi velocity of conduction electron is
A) 0.98 × 106 m/s        B) 1.39 × 106 m/s        C) 2.46 × 105 m/s        D) None of these        (04 Marks)
b. Obtain the expression for electrical conductivity on the basis of free electron theory of metals.                                                                                                                          (06 Marks)
c. Explain how quantum free electron theory succeeds in overcoming the drawbacks of classical free electron theory.                                                                                                                         (06 marks)
d. Calculate the probability of an electron occupying an energy level 0.02 eV above the Fermi level and 0.02 eV below the Fermi level at 200 K.                                                                      (04 marks)

4 a. i) Hysteresis loss occurs when the magnetic material is subjected to
      A) DC voltage     B) AC voltage     C) Both AC and DC voltage           D) none of these
    ii) Which one of the following is a piezoelectric material?
      A) Lead                 B) Mica      C) Iron                 D) Quartz
   iii) If two electric charges are q separated by a distance L, dipole moment of the system is
      A) q/L                   B) L/q              C) qL               D) q/L2
   iv) The polarization that occurs in the frequency range 1013 to 1016 Hz is
     A) Electronic                      B) Orientational     C) Ionic                D) Space charge          (04 Marks)
b. Derive an expression for internal field in the case of one dimensional array of atoms in dielectric solids.                                                                                                                                               (07 Marks)
c. What are soft magnetic materials? Discuss their properties.                                               (05 Marks)
d. A NaCl crystal is subjected to an electric field of 1000 V/m and the resulting polarization is 4.3×10-8 c/m2.            Calculate the static dielectric constant of NaCl.                                            (04 Marks)

PART-B
5 a. i) Emission of a photon by an excited atom due to interaction of external energy is called
        A) Spontaneous emission   B) Stimulated emission        C) Induced absorption  
       D) Light amplification
    ii) ) Let n1 be the number density of lower energy E1 and n2 be the number density of higher energy E2, if  n2>n1 is called
A) Thick population       B) Inverted population         C) Normal population        D) No population
   iii) The relation between Einstein’s coefficient’s A and B is
           A)                         B)                    C)                         D)        
   iv) Pumping process used in diode laser is
        A) Optical pumping         B) Forward bias            C) Electric discharge             D) None of these
 (04 Marks)
b. Obtain an expression for energy density of radiation under equilibrium condition in terms of Einstein coefficient.                                                                                                                        (07 Marks)
c. Describe the recording and reconstruction processes in holography, with the help of suitable diagrams.                                                                                                                         (05 Marks)
d. A ruby laser emits pulse of 20 ns duration with average power per pulse being 100 kW. If the number of photons in each pulse is 6.981 × 1015, calculate the wavelength of photons.   (04 Marks)
           
6 a. i) Superconductors are
        A) diamagnetic                B) paramagnetic      C) ferromagnetic             D) antiferromagnetic
    ii) In a single mode fiber, the diameter of the core is nearly equal to 
         A) 125 mm                        B) 100 mm                   C) 50 mm                         D) 10 mm
   iii) Attenuation in the optical fiber causes due to
       A) Absorption         B) Scattering            C) Dispersion                D) All the three
   iv) Meissner effect will take place in 
A) Solid      B) Super conducting magnet        C) Maglev vehicle         D) MRI              (04 Marks)
b. Obtain an expression for numerical aperture and arrive the condition for propagation. (06 Marks)
c. Give a brief account of SQUID.                                                                               (06 Marks)
d. A fiber 500m long has an input power of 8.6 mw and output power 7.5 mw. What is the loss specification in cable?              (04 Marks)

7 a. i) Four types of Bravais lattices are observed in
A) Rhomohedral system                      B) Orthorhombic system
C) Triclinic system                  D) Monoclinic system
    ii) A plane intercepts at a, b/2, 2c in a simple cubic unit cell. The miller indices of the plane are
         A) (214)      B) (241)      C) (421)           D) (124)
iii) The packing factor for fcc structure is
A) 52%            B) 68%            C) 92%            D) none of these
iv) The miller indices of the plane parallel to the x and y axes are
A) (100)                B) (010)                       C) (001)                       D) (111)                                              (04 Marks)
b. With a neat figure, explain the structure of diamond and show that atomic packing factor of diamond is 0.34.             (08 Marks)
c. How do you find Miller indices of a given plane?                                                 (04 Marks)
d. The minimum order of Bragg’s reflection occurs at an angle 200 in the plane [212]. Find the wavelength of X-ray if lattice constant is 3.615 Å.                                                  (04 Marks)

8 a. i) The state of matter around nanosize is known as
A) solid state   B) liquid state C) mesoscopic state    D) macroscopic state
   ii) In a carbon nanotubes, the bond between the carbon atoms is
A)  metallic     B) ionic           C) covalent      D) hydrogen
   iii) Elastic behavior of the liquid is characterized by its
A) Young’s modulus    B) Rigidity modulus             C) bulk modulus         D) Poisson’s ratio
    iv) Ultrasonic waves are produced by
A) Electromagnetic induction             B) Inverse piezoelectric effect
C) Electronic tuning fork                    D)Piezoelectric effect                                                 (04 Marks)
b. Write a note on carbon nanotubes. Discuss the  various quantum structures.                    (08 Marks)
c. Explain the principle and method of nondestructive testing of material using ultrasonics.
(08 Marks)





1 comment:

Suresh Shenoy said...

Thanks.Almost same questions asked this time.Kindly give multiple choice question answers.