Jawaharlal Nehru Technological University Kakinada 2012-1st Year B.Tech 1st st semester Engineering Physics R10 Set no:2 - Question Paper

Set Code No: R10103 / R10
No. 2
I B.Tech I Semester Regular/Supplementary exams January 2012
ENGINEERING PHYSICS - I (Common to all branches)
Time: three hours Max Marks: 75 ans any 5 ques. All ques. carry equal marks
1.(a) 2 independent non-coherent sources of light cannot produce an interference trend.
Why?
(b) With ray diagram explain the theory of thin films and derive the condition for
constructive and destructive interference in the case of reflected system.
(c) A parallel beam of light ( ? = 5890x10-10m ) is incident on a thin glass plate (µ = 1.5 ) such that the angle of refraction into the plate is 60o. compute the smallest thickness of plate which would appear dark by reflection.[3M + 8M + 4M]
2.(a) elaborate the kinds of diffraction and provide the differences ranging from them.
(b) find the condition for primary and secondary maxima in Fraunhofer diffraction due to
single slit and derive an expression for width of the central maxima.[6M + 9M]
3.(a) elaborate the quarter and half wave plates?
(b) Derive the expressions for thickness of quarter and half wave plates.
(c) Plane polarized light passes through a quartz plate with its axis parallel to the face. compute the thickness of the plate so that the emergent light may be plane polarized. For quartz µ
e= 1.553, µo= 1.542 ? = 5.5x10-5cm.[3M + 8M + 4M]
4.(a) discuss the unit cell and lattice parameters. What is primitive cell and how does it differ
from unit cell.
(b) define the BCC crystal structure and find the expression for its packing factor.
(c) Iron has BCC structure beneath 910 oC and is FCC structure above 910 oC. The atomic radius of an atom is the identical in both the cases. compute the ratio of the packing densities of bulk iron in the 2 structures at beneath 910 oC.[4M + 7M + 4M]
5.(a) Sketch the ( one two 2) and ( 0 2) planes in a cubic unit cell.
(b) State and derive Braggs legal regulations.
(c) How do distinguish ranging from the simple cubic, BCC and FCC using powder X-ray
diffraction data?[4M + 5M + 6M]
6.(a) define the different methods of pumping lasers with suitable examples.
(b) define the construction and working of semiconductor laser.[5M + 10M]
7.(a) describe acceptance angle and numerical aperture. Derive the expressions for for both of
them.
(b) compute the number of modes propagating in an optical fiber of core of 6µm diameter,
(given that the indices are 1.45 and 1.44 for core and cladding respectively) while operated at a wavelength of 0.623 µm.[11M + 4M]
8.(a) discuss the basic principle of ultrasonic testing
(b) elaborate the advantages and limitations of ultrasonic testing.[5M + 10M]

Earning:   Approval pending.