Physics
Mahatma Gandhi Central University, Bihar
B.Tech Computer Science & Engineering
Semester 1 Examination, 2023
Physics (CSET3101)
Assessment Questions
Physics (CSET3101) - 2023
SECTION – A
Multiple Choice Questions. Attempt all questions. Each question carries one mark.
- 1
Distinguish between the mechanism and characteristics of spontaneous emission and stimulated emission.
- 2
A device which converts electrical energy in the form of a current into optical energy is called as
- 3
The radion emission process (emission of a photon at frequency) can occur in ..... ways.
- 4
Which process gives the laser its special properties as an optical source?
- 5
Which method can be used to distinguish between the two types of carriers?
- 6
It is a passive device which allows the flow of optical signal power in only one direction and preventing reflections in the backward direction.
- 7
How does a semiconductor behave at absolute zero?
- 8
Hot bodies emit a specific type of radiation. What are they called?
- 9
Which of the following may not be conserved in a photon-particle collision?
- 10
What is the frequency of a photon having energy ?
SECTION – B
Write briefly in 250 words (Short Answer Questions- 20 Marks) Attempt ANY FOUR questions out of the followings. Each question carries 5 Marks.
- 1
Give the construction and working of semiconductor laser. Draw necessary energy level diagrams.
- 2
Discuss the phenomenon of Fraunhofer’s diffraction at a single slit and derive expression for the intensity of diffracted light.
- 3
Explain the essential requirement for production of laser action?
- 4
Distinguish between the mechanism and characteristics of spontaneous emission and stimulated emission.
- 5
Draw an intensity distribution graph for diffraction due to a single-slit. Differentiate between interference and diffraction.
- 6
What is pumping process and population inversion?
SECTION – C
Write in 500 words (Long Answer Questions – 30 Marks) Attempt ALL questions having internal choices. The question carries 10 marks.
- 1
Answer any ONE of the following
(a)Derive the expression for the critical angle and numerical aperture of LASER in terms of fractional refractive index change. Calculate the fractional refractive index change for an optical fibre if the core and cladding refractive indices are 1.563 and 1.498.
OR
(b)Explain the formation of depletion region and barrier potential in PN junction diode. Can we quantify the behavior of the PN junction through the use of an equation? Explain it & name the scientist who derived it.
- 2
Answer any ONE of the following
(a)Draw schematic diagram of four point probe method. Explain it too.
OR
(b)Write about Newton's Rings, Principle of Newton's Rings formation and application of Newton's ring. Why is the center of Newton's rings dark?
- 3
Answer any ONE of the following
(a)Explain the formation of energy band? Explain VI characteristic and its temperature dependence for semiconductors? Why is Zener Diode used as a regulator?
OR
(b)Write about any LASER and explain about the working principal, with appropriate diagram. Calculate the wavelength of laser emitted from an extrinsic semiconductor laser, if the band gap is 0.02eV.