Nalanda Open University Annual Examination - 2013 B.Sc. Physics (Honours), Part-II(Electrostatics, Magnetism, Current Electricity & Modern Physics)Paper-IV Time: 3.00 Hrs. Full Marks: 80 Answer any five questions. All questions carry equal marks. 1. Define electromagnetic field vectors E D B H rrrr , , & and find the boundary conditions which the time dependent field vectors satisfy at the interface between two different media. 2. Express Laplace's equation in Cartesian, Spherical Polar and Cylindrical Coordinates. Give the importance of this equation. What is Poisson's equation? 3. Describe Langevin's Theory of paramagnetism. How was this extended by Weiss to explain the phenomenon of ferromagnetism? 4. Describe, with theory the construction and action of a moving coil ballistic galvanometer. Give some of the important applications of this galanometer. 5. Obtain an expression for the growth and decay of charge in a condenser through a resistance. What is the time constant of the circuit? 6. Obtain the resonance frequency of a series resonant circuit. Discuss the sharpness of the resonance of the circuit. 7. Explain the working of Anderson's bridge for measurement of the inductance of a coil with the help of necessary circuit diagram and vector diagram. 8. Describe Millikan's experiment to find the charge of an electron. 9. Write short note on any two of the following: (a) Liquid drop model (b) Fermi Gas Model (c) Shell model 10. State and explain Compton effect. How do you experimentally find the change in wavelength predicted by Compton? What is Compten Wavelength.