Question 1) Answer the following questions.
a) Write down different polarization mechanisms in dielectrics?
b) Iron is a ferromagnetic material but a piece of iron does not ordinarily behave as a magnet. Describe.
c) Describe the meaning of stimulated emission.
d) Write down the differences between step-index and graded-index fibers.
e) What is the electric flux through a closed surface surrounding an electric dipole? Describe.
f) Is the earth an inertial frame? If not, why?
g) Write the Bragg's equation for X-ray diffraction and explain the meaning of various symbols in it.
h) What is the method of pumping in a Ruby laser?
i) State the conditions which a physically acceptable wave-function should obey.
j) Write down some significant changes that occur in substances when they change from their normal state to the superconducting state.
Question 2)a) Write down the four Maxwell's equations in differential form. Explain the significance of each. Describe Maxwell's modification of Ampere's law.
b) Dielectric constant of a gas at NT.P. is 1.00074. If the gas is held in an external field of 3 x 104V/m, compute the dipole moment of each atom of the gas.
Question 3)a) What are the distinctive characteristics of ferromagnetism? Describe the domain theory of ferromagnetism.
b) The magnetic susceptibility of silicon is -4.2x10-6. Determine its magnetization and the magnetic flux density when it is placed in magnetic field of strength 1.2x105 A/m.
Question 4)a) What are Einstein's coefficients? Describe their meaning and derive the relation between them.