university question

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Reg. No. :
Question Paper Code : 10004
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B.E./B.Tech. DEGREE EXAMINATION, JANUARY 2011.
First Semester
Common to all branches
182101 – ENGINEERING PHYSICS – I
(Regulation 2010)
Time : Three hours Maximum : 100 marks
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Answer ALL questions.
PART A — (10 × 2 = 20 marks)
1. Can we use a copper rod in a magnetostriction generator? Why?
2. An ultrasound pulse sent by a source in sea is reflected by a submerged target
at a distance 597.50m and reaches the source after 0.83 seconds. Find the
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velocity of sound in sea water.
3. Can a two-level system be used for the production of laser? Why?
4. Mention any two differences between a hologram and a photograph.
5. What is called mode of propagation in optical fibers?
6. Mention the properties of detectors used in fiber – optic communication.
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7. Calculate the energy in eV of a photon of wavelength 1.2 A . (Planck’s constant
= 6.62 × 10–34 Js. speed of light = 3 × 10 8 m / s ).
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8. Mention the physical significance of wave function of matter waves.
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9. The interplanar distance of (110) planes in a BCC crystal is 2.03 A . What is
the lattice parameter of the crystal?
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10. List the different types of point defects.

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PART B — (5 × 16 = 80 marks)
11. (a) (i) Define piezoelectric effect. (2)
(ii) With a neat diagram, explain the construction and working of a
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piezoelectric oscillator. (12)
(iii) Briefly outline the emulsification using ultrasonic waves. (2)
Or
(b) (i) What is acoustic grating? With a neat diagram, explain the theory
and use of it to determine the ultrasonic velocity in a liquid. (2 + 8)
(ii) Briefly outline the various industrial applications of ultrasonic
waves. (6)
12. (a) (i) With a neat diagram, explain the construction and working of a
(ii)
CO2 laser. 28
Outline the use of lasers in heat treatment.
(12)
(4)
Or
(b) (i) Explain the principle, construction and working of a semiconductor
diode laser with necessary diagrams. (12)
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(ii) What are heterojunction lasers? Mention any two advantages of
them. (2 + 2)
13. (a) (i) Define the numerical aperture of an optical fiber. Derive an
expression for it. (2 + 8)
(ii) Explain the double crucible method of drawing optical fiber with
neat diagram. (6)
Or
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(b) (i) Discuss the mechanisms of attenuation, dispersion and bending
losses in optical fibers. (10)
(ii) Explain the principles of working of temperature and displacement
sensors using optical fibers. (6)
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14. (a) Explain the theory of blackbody radiation due to Planck. Also discuss the
limits of high temperature and low temperature of the result. (10 + 6)
Or
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(b) (i) Derive the time-dependent (1–D) Schr&&edinger equation from
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fundamentals. (12)
(ii) Find the change in wavelength of an X-ray photon which is
scattered through an angle of 90o by an electron. (Planck’s constant
= 6.62 × 10-34 Js; rest mass of electron = 9.1 × 10-31 kg; speed of light
= 3 × 108 m/s). (4)
15. (a) (i) Write the standard crystal systems corresponding to with their
lattice parameters. What are Bravias Lattices? (7)
(ii) Explain the procedure to obtain the Miller indices of crystal planes.
Also deduce a relation between Miller indices and the inter-planar
distance. (3 + 6)
(b) (i)
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The density of BCC iron is 7860 kg/m3 and its atomic weight is
55.85. Calculate its atomic radius. (6)
(Avogadro number = 6.023 × 1026/k mole)
(ii) Deduce the c/a ratio and packing factor of standard HCP crystal.
(10)
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