Bapatla Engineering College::Bapatla (Autonomous)

¼ B.Tech- Short answer model questions

Subject: Engineering Physics-I (112)

UNIT-I

OPTICS

INTERFERENCE:

1. What is the superposition principle?

2. Define constructive and destructive interference.

3. Give few conditions for sustained interference.

4. Distinguish between longitudinal and transverse waves, give one example for each.

5. Give the relation between phase difference and path difference.

6. How intensity is related to amplitude?

7. What is phase change on reflection from surface of dense film?

8. What is cosine law?

9. Give the conditions for maximum and minimum intensity for the reflected light from a thin dense

film.

10. What is the physical phenomenon behind the brilliant colors of soap bubbles and oil slicks?

11. What is the basic principle of Michelson’s interferometer?

12. What is the role of compensating glass plate in Michelson’s interferometer?

13. Is Michelson’s interferometer is equivalent to an air film or glass film?

14. What should be the shape of fringes to find wavelength of monochromatic light using

Michelson’s interferometer?

15. What is the use of movable mirror in Michelson’s interferometer?

DIFFRACTION:

1. Give few differences between Fresnel & Fraunhofer diffraction.

2. Which point in the diffraction pattern, due to single slit, possesses the maximum intensity?

3. What is the difference between single slit and N-slits diffraction pattern?

4. Give one example each for Fresnel & Fraunhofer diffraction (optical devices).

5. Define dispersive power of grating.

6. Which color in the “VIBGYOR” has more angle of diffraction in any order?

7. What is the proportionality relation between wavelength and angle of diffraction?

8. What is Rayleigh’s criterion?

9. What is the effect of (a) increasing the slit width ‘e’ (b) increasing the slit separation‘d’(c)

increasing the wavelength ‘λ’ on fringe pattern?

10. In what way are interference and diffraction similar? In what way are they different?

11. Why does a diffraction grating have (a) closely spaced rulings (b) a large number of rulings?

12. Give the mathematical relations for the resolving power and dispersive power of grating.

POLARISATION:

1. How can you conform that light is transverse in wave nature?

2. Why sound waves can not show polarization effects?

3. What is Brewster’s law?

4. What is Malus law?

5. What is the angle between reflected and refracted beams at polarizing angle?

6. What is meant by optically isotropic medium?

7. What is meant by double refraction?

8. Distinguish between uniaxial and biaxial crystals also give one example each

9. Give example of crystals exhibiting the property of double refraction.

10. Give few differences between o-ray & e-ray.

11. Does the e-wave in doubly refracting crystal always travel at a speed given by “C/ne”?

12. What are the corner angles in an ungrounded Nicol’s prism?

13. What is the role of “Canada balsam” material in Nicol’s prism?

14. What is the use of quarter and half wave plates?

15. Would you expect a quarter wave plate made from calcite to be thicker than one made from

quartz?

UNIT-II

LASERS & FIBEROPTICS

LASERS:

1. Expand ‘LASER’.

2. What are additional qualities of LASER than ordinary light?

3. Distinguish between spontaneous and stimulated emission.

4. What are metastable states?

5. What is meant by population inversion and cavity resonator?

6. What is the active medium in Ruby LASER and He-Ne gas LASER?

7. Give the advantages and disadvantages of Ruby LASER and He-Ne gas LASER?

8. Why junction diode should be connected in forward bias for lasing action?

9. Give example of semiconductor LASER material?

10. Distinguish between direct band gap and indirect band gap semiconductor.

HOLOGRAPHY:

1. Who invented holography?

2. What is the basic principle of holography?

3. Distinguish between conventional photography and holography.

4. What is meant by acoustic holography?

5. Why LASER is preferred for holography?

6. Why object beam should be identical with reference beam to record hologram?

7. Give few applications of holography.

FIBER OPTICS:

1. What is the advantage of fiber optic communication?

2. What is the basic principle of fiber optics?

3. Distinguish between step-index and graded- index optical fiber.

4. What is the typical size of core diameter in single-mode and multimode fiber?

5. What happened to beam if incidence angle is more than acceptance angle of fiber?

6. What is the typical value of core-cladding index difference ‘∆’?

7. Give the relation between numerical aperture ‘NA’ and core-cladding index difference‘∆’?

8. What is the physical significance of numerical aperture?

9. What are the priorities of core material?

10. What is meant by signal attenuation or fiber loss?

UNIT-III

ELECTRICITY &MAGNETISM

1. Define electric flux.

2. Define Gauss’s law in static electricity.

3. What is the unit of solid angle?

4. What is meant by Gaussian surface?

5. What is the normal electric flux through the closed surface if charge lies out side?

6. Define Gauss’s law in magnetism.

7. What is meant by cyclotron frequency?

8. Give few limitations of Cyclotron.

9. Give few applications of Cyclotron.

10. Why neutral particles can not be accelerated with Cyclotron?

11. Define Hall-effect.

12. What is Hall coefficient?

13. Give few applications of Hall-effect.

14. What is Faraday’s law of induction?

15. What Lenz’s law?

16. What is Ampere’s law?

17. What is meant by displace current?

18. What is wrong with Ampere’s law modified by Maxwell?

19. Give expressions for energy density in electric field and magnetic field.

20. How damped harmonic oscillations are analogous to series LCR circuit applied with alternative

emf.

21. What is the velocity of electromagnetic wave in free space?

22. Give transverse wave equation in stretched string in sonometre.

23. Give electromagnetic wave equations with electric and magnetic fields.

24. Define Poynting vector and give its units.

25. What is meant by radiation pressure?

26. Define capacitive and inductive reactance and impedance.

27. What is the relation of resistance and impedance in series LCR circuit at resonance?

28. Show the variation of current and voltages versus frequency in series LCR circuit applied with

AC voltage

29. What are the units of inductance and capacitance?

30. Give the permittivity and permeability values in free space.

UNIT-IV

MODERN PHYSICS

1. What is meant by dual nature of light?

2. Give few properties of light exhibiting particle nature and wave nature separately.

3. What is de Broglie’s hypothesis?

4. What are the properties of matter waves?

5. How matter wave velocity is larger than velocity of light?

6. What is the de Broglie’s wavelength of electron accelerated with potential of ‘V’?

7. What is the result of Davisson-Germer’s experiment?

8. Why X-rays are appropriate radiation to study the diffraction effects in crystals?

9. Give Heisenberg’s uncertainty principle.

10. Give Schrödinger’s time independent wave equation in one dimension.

11. What is the physical significance of wave function ‘Ψ’?

12. What is meant by normalization condition in quantum mechanics?

13. Give the quantized energy values and wave function for a particle trapped in one dimensional

well of infinite height.

14. What is meant by quantum mechanical tunneling?

15. Who invented “Scanning Tunneling Microscope (STM)”?

16. Give few applications of STM?

17. What are the basic principles of STM?

18. Define Piezo electric effect?

19. Which nuclear radiation is emitted based on quantum mechanical tunneling?

20. Give the equation for relativistic energy.

Compiled by Dr.Ch.Anjaneyulu, department of Physics, Bapatla engineering college, Bapatla