1. (a) Explain the principle of superposition of waves.
(b) Explain the phenomenon of interference.
(c) With relevant diagram explain Young’s experiment on the basis of wave theory.
2. (a) What is meant by diffraction of light? Explain it on the basis of Huygen’s wave theory.
(b) What are the types of diffraction and give the difference between them.
(c) What is the difference between Interference and Diffraction?
3. (a) Distinguish between polarized and unpolarized lights.
(b) What is Brewster’s law? Explain how this can be used to find the polarizing angles of various crystals.
(c) Find the Brewster angle for a glass slab (μ =1.5) immersed in water (μ =4/3).
4. (a) Give the various pumping mechanisms that are adopted in lasers.
(b) Discuss the essential features of a laser beam.
(c) Explain the uses of lasers in various fields.
5. (a) Define molar specific heat of a solid.
(b) Discuss the merits and demerits of Einstein’s theory of specific heat of solids.
(c) What are phonons?
6. (a) Discuss, in detail, the theory of dielectrics in alternating field.
(b) A dielectric material has εr= 12 and it contains 5 × 1028 atoms/ m3. Calculate the electronic polarizability assuming Lorentz field.
7. (a) What are paramagnetic materials? Explain.
(b) Obtain an expression for paramagnetic susceptibility (χ). How does the paramagnetic susceptibility of a material vary with temperature?
(c) A paramagnetic material has 1028 atoms per m3. Its susceptibility at 350 K is 2.8 × 10−4 . Calculate the susceptibility at 300 K.
8. (a) What are the general requirements for spacecraft materials?
(b) What are the different classifications of the spacecraft materials? Explain how they are classified?