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Sample Exam Paper

BAS101Sample Examination Paper — I

Course: Engineering Physics (BAS101)Programme: B.Tech. — Semester I (Common to all branches)
Time: 3 HoursMaximum Marks: 70

General Instructions:

  1. Attempt all questions from Section A.
  2. Attempt any two parts from each question in Section B.
  3. Attempt any two questions in full from Section C.
  4. Assume any missing data suitably and state it clearly.

Section A — Short Answer (Compulsory)

  1. Define an inertial frame of reference with an example. (2 marks)
  2. State the two postulates of Einstein's special theory of relativity. (2 marks)
  3. What is meant by coherent sources? Why are they essential for sustained interference? (2 marks)
  4. Write the condition for the nth dark ring in Newton's rings experiment (by reflection). (2 marks)
  5. Distinguish between a quarter-wave plate and a half-wave plate. (2 marks)
  6. Define numerical aperture of an optical fibre. (2 marks)
  7. What is population inversion? Why is it necessary for laser action? (2 marks)

Section B — Attempt any two parts of each

  1. Derive the Lorentz transformation equations for space and time between two inertial frames. (5 marks)
  2. Describe Fresnel's biprism experiment and derive an expression for the fringe width. (5 marks)
  3. Discuss single-slit Fraunhofer diffraction and obtain the condition for minima. (5 marks)
  4. Explain the construction and working of a Nicol prism as a polarizer. (5 marks)
  5. Explain the principle, construction and working of a Ruby laser with a neat energy-level diagram. (5 marks)

Section C — Attempt any two questions in full

  1. Derive expressions for length contraction and time dilation from the Lorentz transformation, and briefly discuss their physical significance with a numerical example. (10 marks)
  2. Describe the theory of Newton's rings by reflected light. Derive the expression for the radius of the nth dark ring and explain how the experiment is used to determine the wavelength of monochromatic light. (10 marks)
  3. Describe the construction and working of a plane diffraction grating. Derive the condition for principal maxima and obtain an expression for the resolving power of the grating. (10 marks)
  4. Explain the principle of holography. Describe how a hologram is recorded and reconstructed, and list two practical applications of holography. (10 marks)
  5. Discuss the propagation mechanism of light in an optical fibre. Derive an expression for the numerical aperture and explain the terms attenuation and dispersion in the context of fibre-optic communication. (10 marks)