Engg. Physics I: paper set 1:Quantum Mechanics, Semiconductors, Ctrystallography ETC

Paper Set -  I

Subject: Engineering Physics I

Time: 2:00 Hours ]                                                                                 [  Marks: 40 

            INSTRUCTIONS TO CANDIDATE

      All Questions carry Equal Marks as indicated.   

      Solve FOUR questions as instructed.

      Assume suitable data.

       Draw neat sketches wherever necessary.

      Use of calculator is permitted.

Q1. (a)Write Plank’s Quantum Hypothesis with energy level diagram                                       (2)

       (b)State any four Properties of Photons.                                                                                (2)

       (c)What is Compton Effect? Explain Compton shift with equation. Prove it graphically    (3)

       (d)If the incident radiation is 1.16 Ă. Find the wavelength of scattered radiations 

           at angle 45⁰.                                                                                                                        (3)

OR

Q2. (a)Prove that light exhibit both wave as well as particle nature.                                           (2)

       (b)Explain that the wavelength of Macroscopic bodies is insignificant in comparison

             to the size of the bodies. Calculate the value for wavelength.                                         (3)

       (c)Explain this statement with the help of Davisson & Germer  Experiment                (3)

       (d)Find the De-broglie wavelength of an electron accelerated through a potential 

            difference of 168 volts.                                                                                                      (2) 

Q3. (a)Define: Crystal Structure,Non primitive Cell, lattice Planes.                                            (3)

       (b)Find  out Atomic Packing Fraction and Density in SC and FCC                                      (2)

       (c)Differentiate between Tetrahedral and Octahedral Voids.                                                 (2)
       (d)Nickel crystallizes in a FCC crystal. The edge of unit cell is 3.52 Å.  
           The its atomic weight of nickel is 58.710 Kg/Kmol. Determine the density of metal.     (2)

OR

Q4. (a) Deduce a relation between an interlinear distance d and the Miller indices

            of the planes for cubic crystal.                                                                                          (4) 
       (b) Draw the following Miller Indices Priciple planes .                                                        (3)

       (c) Explain and deduce Bragg’s Law for X-Ray diffraction.                                                (3)

Q5. (a) Explain how wave packet are formed taking it in the form of beats.                              (3)
      (b)Explain the application of Heisenberg’s Uncertainty principle with the help of 
           macroscopic body.                                                                                                             (3)

       (c)Explain the interpretation of wave function and write the normalization of 

            wave function.                                                                                                                  (2) 
       (d)Write 3D time independent Schrodinger Equation.                                                          (2)

OR

Q6. (a)Write one dimensional time dependent Schrodinger Equation.                                       (2)

       (b)Show that the Wave function for particle confined in an infinite one dimensional
          potential well of length ‘l’ is given by Ψn(x) = √2/l sin(nПx/l)                                         (4)

       (c)Discuss the Tunnling effect with the help of Schrodinger Equation.                                (2)

       (d)Calculate the value of lowest three energy state for electron confined in the infinite

            potential well of width 10 Ǻ (m = 9.11 x 10^-31 Kg, h = 6.626 x 10^-34 J.s)                     (2)

 Q7. (a)Explain p-type and n- type semiconductors with suitable diagram.                                (3)

       (b)Write down the Fermi - Dirac Equation for the probability of occupation of  an 

             energy level E by an electron.                                                                                         (4)

       (c)Explain how fermi level changes with increasing amounts of impurity in n-type

           and p-type Semiconductor.                                                                                                (3)

OR

Q8. (a)What is Hall Effect with suitable experimental diagram?                                                (3)

       (b)Calculate each of the following parameters Hall Voltage, Hall Coefficient,

            Hall Mobility.                                                                                                                   (5)

       (c)Mention the importance of  Hall Effect in the field of Semiconductor.                          (2)