F. E. (Semester – II),2014 Question Paper,APPLIED SCIENCE – II (Physics),University Of Pune Question Paper

University Of Pune Question Paper F. E. (Semester – II) Examination, 2014 APPLIED SCIENCE – II (Physics) (Old) (2008 Course) Time : 2 Hours Max. Marks : 50 Instructions : 1) Answer any three questions (Q.1 or Q.2, Q.3 or Q.4, Q.5 or Q.6) 2) Figures to the right indicate full marks. 3) Neat diagrams must be drawn wherever necessary. 4) Use of electronic calculator is allowed. 5) Assume suitable data if necessary. Constants : 1) Mass of electron (me) = 9.1 × 10–31kg. 2) Charge on electron (e) = 1.9 × 10 –19 C 3) Mass of neutron =(mn) = 1.675 × 10–27kg. 4) Plank’s Constant (h) = 6.63 × 10–34 J.s 5) Velocity of light in vacuum (c) = 3 × 108 m/s. 1. a) State and explain Heisenberg’s Uncertainty Principle. Illustrate this principle with an experiment on diffraction of electrons. 7 b) Derive Schrodinger’s time independent equation. 6 c) Calculate the de-Broglie wavelength associated with 1 Mev neutron. 4 OR 2. a) Derive equation of energy and wave function when a free particle is trapped in an infinite potential well. 7 b) Explain the concept of group velocity. Show that group velocity is equal to the velocity of the particle. 6 c) Calculate energy level difference between first two excited state of a neutron trapped in infinite potential well of width 10–15 m. 4 3. a) With the help of energy level diagram explain construction and working of He-Ne laser. 6 b) What is Critical Magnetic Field ? Explain Type–I and Type–II superconductors. 6 c) Explain for laser (a) Stimulate emission of radiation (b) Pumping. 4 OR 4. a) What is superconductivity ? Explain BCS theory of superconductivity. 6 b) With the help of energy level diagram explain construction and working of Ruby laser. 6 c) Explain for superconductor (a) Transition temperature (b) Persistent current. 4 Seat No. P.T.O. [4656] – 23 5. a) What is band gap energy ? Explain classification of solids into conductors, semiconductors and insulators on the basis of band theory of solids. 7 b) What are the different methods for synthesis of nanoparticles ? Explain any one method in details. 6 c) A strip of copper of thickness 1.5 × 10–4 m is placed in a magnetic field of 1 T perpendicular to the plane of the strip and a current of 10 A is setup in the strip. What Hall voltage would appear across the width of the strip if concentration of charge carries in copper is 8.5 × 1028 electrons/m3. 4 OR 6. a) Explain the construction and working of solar cell. Explain its IV characteristics. 7 b) Explain any two properties of nanoparticles. 6 c) A germanium sample has 4.56×1022 atoms/cc and a donor impurity in the ratio of one part per 1010 is added to create an N type semiconductor. If the mobility of charge carries is 3900 cm2/ V–s, find the conductivity of silicon. 4 —————— B

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