Important Questions Physics

Important Questions Physics

IMPORTANT QUESTIONS – PHYSICS

  1. What are seven crystal systems and fourteen Bravais lattices? Describe in detail.
  2. Define the following terms (i) number of atoms per unit cell (ii) atomic radius (iii) Packing factor. Calculate these terms for Simple cubic, Body centered cubic, Face centered cubic structure.
  3. Show that the distance between the successive planes of miller indices(hkl)for cubic lattice is given by

dhkl = a / [h2+k2+l2]1/2.

  1. Draw and explain the characteristics of NaCl and Diamond crystal structure.
  2. Describe the construction and working of Bragg’s X-ray spectrometer. How it is used for determining the crystal structure.
  3. Discuss the different types of polarization?
  4. Explain the behavior of dielectric in an alternating field. What is relaxation time?
  5. What is Internal field? Derive an expression for Lorentz internal field in dielectric and hence deduce Clausius-Mossotti relation.
  6. Distinguish between diamagnetic, paramagnetic and ferromagnetic materials. Giving one example of each, describe about their uses.
  7. Discuss Langevin’s theory of diamagnetism and show that diamagnetic susceptibility is negative and independent of temperature and field strength.
  8. What is Hysteresis? Explain Hysteresis loss. How hysteresis curve is used to select the materials for the construction of

(i)Permanent magnets (iii) Electromagnets

(ii)Transformer cores

  1. Write the Maxwell equation in differential and integral forms .Explain the physical significance of each equation.
  2. Prove that the velocity of plane electromagnetic wave in vacuum is given by

c = 1/ (µ0ε0)1/2

  1. What is Poynting vector? Discuss the work energy theorem for the flow of energy in an electromagnetic field.
  2. Derive electromagnetic wave equations in non-conducting medium and discuss its solutions.
  3. Define Fermi Dirac probability distribution function. Show that at all temperatures, probability of occupancy of Fermi level is50%.
  4. What do you mean by conductivity? Derive an expression for the electrical conductivity of an intrinsic and extrinsic semiconductors.
  5. What do you mean by Meissner effect? Explain how Meissner effect proves the superconductor is a perfect diamagnetic material.
  6. What are Type I & Type II Superconductors? Explain.
  7. Discuss the formation of Cooper pairs and energy gap in superconductors on the basis of BCS theory.
  8. What are carbon nanotubes? Explain their classification. How carbon nanotubes are synthesized? Discuss their properties and application.
  9. What is chemical vapours deposition technique for the production of carbon nanotubes?
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