Download AKTU B-Tech 3rd Sem 2016-2017 NOE 033 Laser System And Applications Question Paper

Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 3rd Semester (Third Semester) 2016-2017 NOE 033 Laser System And Applications Question Paper

Printed Pages: 4 NOE - 033
(Following Paper ID and Roll No. to be ?lled in your
Answer Books)
Paper ID: 228945 Roll No.
B.TECH
Regular Theory Examination (Odd Sem - 111), 2016-17
, LASER SYSTEM AN D APPLICATIONS
T ime : 3 Hours Max. Marks : I 00
Note : Attempt all sections. If require any missing data;
then choose suitably. ? '
Section - A
1. Attempt all questions in brief. ' (10x2=20)
a) What do understand by Planck?s Hypothesis?
b) Describe wave particle duality in short.
0) Explain the physical signi?cance ofwave ?mction.
d) How is metastable state essential to achieve
population inversion?
e) Describe the factors which cause losses in a laser.
' f) Find the intensity of a laser beam of' 1 OOmW power
and having a diameter of 1.3mm. Assume the
intensity to be uniform.
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g) What is an active medium?
h) What are Dye Lasers?
i) Write few applications of Ruby laser.
j) What is hole?buming in laser gain curve?
Section - B
Attempt any three of the following: (3X 10:30)
a) What is Compton Effect? Derive an expression for
Compton shift. A photon of energy 1.02 MeV is
scattered through 60? by a free electron. Calculate
the energy Of the photon and the electron after
interaction.
b) What are the Einstein?s coef?cients? Establish a
relation between them.
c) Why does a two?level laser not have any physical
signi?cance? Explain working of three and four
level laser systems.
d) What are ionic lasers? Explain the construction and
working of Argon ion laser.
e) Write a note on application of laser in medicine and
surgery.
? Section - C
Attempt any one part of the following: (1 X 10=10)
a) By using Heisenberg?s uncertainty principle, show
that an electron cannot exist inside the nucleus but
proton can exist.
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b) Describe Davisson and Germer?s electron
diffraction experiment to demonstrate the wave.
character of electron.
Attempt any one part of the following : (1 X 10=10)
a) What is the concept of coherence in laser? Derive
a relation between coherence length and line width.
b) What is an optical resonator and explain its various
con?gurations.
Attempt any one part of the following! (1 X 10=10)
a) What do you mean by loop gain? If active medium
gain in laser is 1.03 with length 30 cm. Theloss
coef?cient is a = 1.35 X 10?4 cm" .The re?ection
coef?cients of the mirrors are 0.99 and 0.94
respectively. Calculate its loss factor, loop gain and
gain coef?cient. '
b) What do you mean by Q-switching? Describe
various methods of Q-switching in brief.
Attempt any one part of the following: (1X 10=10)
a) Describe the construction and working of He-Ne
laser. Compare it Ruby Laser.
b) Discuss the features, lasing transitions, operations
of Nd?: YAG laser. '
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7. Attempt any one part of the following: ? (1 Xl0=10)
a) What do you mean by material processing? What
are the various. changes that can take place during
material processing?
b) Discuss, how Laser can be used in Metrology?
Physical Constants
Rest mass of electron m0 = 9.1 X 10'3'kg
Rest Mass of Proton mF) = 1.67810?27kg
Speed oflight ' c = 3 x 108 m/s _
Planck?s Constant h = 6.6391064 J-s
Charge on electron e = 1.6><10?l9 C-
_ Boltzmann?s Constant k ? = '1 .38><10'23 J K-1
?????
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