Engineering Physics for B.Tech/B.E model question paper

1(a) What is uncertainty principle? Based on Heisenberg’s uncertainty principle, show that electrons cannot exist    within the nucleus.                                               (06 Marks)   

(b) What is Planck’s radiation law?  Show how Wien’s law and Rayleigh-Jean’s law can be derived from it.                                                                               (05 Marks)

(c) Explain de-Broglie Hypothesis. (4 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 (a/2) marked symmetrically at the centre of the box?                                            (05 Marks)

2(a)Write a note on expectation value. (4 Marks)

(b) Set up time independent one dimensional Schrödinger equation.         (06 Marks) 

(c) Define group velocity. Derive relation between group velocity and phase velocity.                                                                                                                   (06 Marks)

(d) Estimate the time spent by an atom in the excited state during the excitation and de-excitation processes, when a spectral line of wavelength 546 nm and width 10^-14 m is emitted.                                                                                                            (04 marks)

3.(a) Explain law of mass action.                                                                       (4 Marks)

(b). Write a short note on Fermi-Dirac statistics                                    (04 Marks)

(c)What is Meissner effect? Distinguish between Type-I and Type-II superconductors.                                                                                                              (06 Marks) 

(d) For intrinsic gallium arsenide, the room temperature electrical conductivity is 10^-6 ohm^-1m^-1. The electron and hole mobilities are respectively 0.85 m²/Vs and 0.04 m²/Vs. Calculate the intrinsic carrier concentration at room temperature.    (06 Marks)

4.(a) Write notes on isotope effect and critical surrent density of superconductors.                                                                                                                                 (04 Marks)        

(b) What is Josephson effect?                                                                          (04 Marks)

(c) Explain Lorentz-Drude theory. Write special comments on positive Hall coefficient of zinc.                                                                                        (8 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)

5.(a) Describe the recording and reconstruction processes in holography, with the help of suitable diagrams.                                                                            (05 Marks)      

(b) Obtain expressions for numerical aperture and acceptance angle of an optical fiber.                                                                                                                    (04 Marks)

(c)  Explain the different types of optical fibers.                                     (04 Marks)      

(d) Describe the construction and working of semiconductor laser. The average output power of laser source emitting a laser beam of wavelength 633nm is 5 mW. Find the number of photons emitted per second by the laser source.                     (07 Marks)

6(a) Explain the crystal structure of sugar crystals. Write notes on Polymorphism and Allotropy.                                                                                                        (08 Marks)       

(b) Obtain an expression for interplanar distance in a cubic crystal in terms of Miller indices.                                                                                                 (04 Marks)

(c) What are unit cell, lattice parameter, Bravaise lattice and coordination number.

(4 Marks)

(d) A monochromatic X-ray beam of wavelength 1.5 Å undergoes second order Bragg reflection from the plane (211) of a cubic crystal, at a glancing angle of 54.38⁰. Calculate the lattice constant.                                                                                  (04 Marks)

7(a) Explain how nanoparticles are synthesised by molecular beam epitaxy method.

(6 Marks)

(b). Describe the arc discharge method of producing carbon nanotubes. (04 Marks)

(c) Write a note on application of nanoparticles in agriculture.                (04 Marks)

(d) Explain the working of SEM. In a SEM, electrons are accelerated by an anode potential difference of 60 kV. Estimate the wavelength of the electrons in the scanning beam.                                                                                                                      (06 Marks)

8(a) What is a shock wave? Mention three applications. Briefly explain Rankine-Hugonit shock equations.                                                                                 (08 Marks)      

(b) Explain the method of production of ultrasonic waves by magnetostriction method.

                                                                                                                        (04 Marks)

(c) What is nondestructive testing? mention some examples.                   (04 Marks)

(d) distinguish between NMR and ESR.                                                            (04 Marks)