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Saturday, August 17, 2013

First/Second Semester B.E. Degree Examination, December 2013 Engineering Physics-Model question paper

USN                                                                     10PHY12/22                                                                                                

First/Second Semester B.E. Degree Examination, December 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

1 a.  i) The law which failed to account for shorter wavelength region of blackbody radiation spectrum is
A) Wien’s law    B) Rayleigh-Jean’s law      C) Planck’s law                   D) Maxwell’s law     
 ii) The group velocity of the particle is 3×106 m/s, whose phase velocity is
A) 6.06×106 m/s                B) 3×1010 m/s     C) 3×106 m/s      D) 1.5×1010 m/s                
       ii) Photoelectric effect establishes
A) wave nature of light    B) particle nature of light   C) dual nature of light           D) None of these
       iv) The Compton wavelength is given by
A) h/m0C2                    B) h2/m0C2           C) h/m0C         D) h2/2m0C
   (04 marks)
   b. Derive de-Broglie wavelength using group velocity.            (05marks)
   c. Describe Davisson and Germer experiment for confirmation of de-Broglie hypothesis (07 Marks)   
   d. Find the de-Broglie wavelength of particle of mass 0.65 MeV/C2 has a kinetic energy 80 eV.    (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 product of uncertainty between angular momentum and angular displacement is
A) ≥ ħ/2p         B) ≥ ħ /4p                                 C) ≤ ħ /4p                 D) ≥ ħ /2
     iii) The ground state energy of an electron in an one dimensional infinite potential well of width 2Å is 16 eV. Its energy in third excited state is
         A) 32 eV                     B) 64 eV                           C) 144 eV           D) 256 eV     
  iv) The wavefunction is acceptable if it is
        A) Finite everywhere                                            B) Continuous everywhere    
        C) Single valued everywhere                               D) All of these            
                                                                                                                                                (04 Marks)
 b. State and explain Heisenberg’s uncertainty principle and prove that nuclei do not contain electron.                                                                                                             (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) According to quantum free electron theory, the energy level in a metal are
       A) Continuous      B) Discrete       C) Overlapping            D) None
    iv) The fermi factor for E = EF at T > 0K is
A) 1        B) ½                       C) 0                       D) 2
                        (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) In the inverse piezo electric effect,
A) Ultrasonic waves are produced     B) electromagnetic waves are produced
C) microwaves are produced      D) none of the above
    ii) If two electric charges are q, separated by a distance L, the dipole moment of the system is
      A) q/L            B) L/q      C) qL                   D) q/L2
   iii) The relation between B, M and H is
      A) H = m0(M+B)     B) M = m0(H+B)           C) B = m0(H+M)           D) None of these
   iv) The relative permeability for diamagnetic materials is
  A) Slightly greater than one   B) Zero     C) less than one      D) very much greater than one                                                                                                                                    (04 Marks)
b. Derive the expression for internal field in solids.                                        (08 Marks)
c. Distinguish between hard and soft magnetic materials.                                            (04 Marks)
d. The atomic weight and density of sulphur are 32 and 2.08 g/cc respectively. The electronic polarizability of the atom is 3.28×10-40 F.m2. If sulphur solid has cubic symmetry, what will be its relative permittivity?                                                                                               (04 Marks)

5 a. i) The emission of photon without aided by any external agency is called
            A) Light amplification    B) Induced absorption     C) Stimulated emission   D) Spontaneous emission   
ii) The life time of an atom at the ordinary excited state is of the order of
A)  few milli second              B) few nano second           C) few micro second       D) Unlimited
   iii) Pumping technique used in He-Ne gas laser is
        A) Forward bias         B) Optical pumping       C) Electrical discharge        D) High injection current                 
   iv) From a broken hologram which is 10% of the original, if reconstruction of image is being done, then
          A)  Only 10% of information of the object can be obtained
B) Complete information of the object is obtained
         C) No information of the object can be obtained                D) None of these  (04 Marks)
b. Obtain an expression for energy density of radiation under equilibrium condition in terms of Einstein coefficient.            (06Marks)
c. Describe the recording and reconstruction processes in holography, with the help of suitable diagrams. (06 Marks)
d. Calculate on the basis of Einstein’s theory the number of photons emitted per second by He-Ne laser source emitting light of wavelength 6328Å with an optical power 10 mW.           (04 Marks)      

6 a. i) The critical temperature of mercury is
         A) 4.2 K                          B) 6.2 K                              C) 7.8 K                D) 20 K
    ii) Attenuation in the optical fiber causes due to
       A) Absorption         B) Scattering            C) Dispersion                D) All the three
   iii) Numerical aperture of an optical fiber depends on
         A) Diameter of the fiber               B) Acceptance angle            C) Critical angle         D) hcore material
   iv) Superconductors are
Diamagnetic B) paramagnetic C) ferromagnetic D) antiferromagnetic             (04 Marks)
b. Discuss BCS theory of superconductor. Explain SQUID.                                        (07 Marks)
c. Describe the point to point communication system, with the help of block diagram.        (05 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) For every rotation by angle q in Bragg’s spectrometer, detector turns by an angle
A) q B)3q C) 4q D) 2q
    ii) APf of diamond crystal structure is
A) 0.68  B) 0.74 C) 0.52  D) 0.34
    iii) In a simple cubic lattice the ratio d100:d110:d111 is
A) 6:3:1           B) √3:√6:1       C) 6:3:√2         D) √6:√3:√2
    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. Discuss the Bravais lattice and any five crystal systems with the help of illustrations.     (07Marks)
c. How do you find Miller indices of a given plane.                                                  (05Marks)
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) Testing of a product without causing any damage is called
A) minute testing         B) destructive testing   C) non-destructive testing       D) random testing
   ii) The state of matter around the nanosize is known as
A) Liquid state B) Plasma state C) Mesoscopic state    D) Solid state  
   iii) In a carbon nanotubes, the bond between the carbon atoms is
A) metallic       B) ionic            C) hydrogen     D) covalent
    iv) A bulk material (three dimensions) reduced in two directions is known as
A) Quantum dot           B) Quantum particle    C) Film                        D) Quantum wire         (04 Marks)
b. What are Nanomaterials? Explain carbon nanotubes and their physical properties. Mention few applications of carbon nanotubes.                                                       (08 Marks)
c. Explain the principle and method of nondestructive method of testing of material using ultrasonics. (08 Marks)

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