Set No. 1

Code No: R05012302

1. (a) Explain the principle of superposition of waves. (b) Explain the phenomenon of interference.

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I B.Tech Semester Supplimentary Examinations, June 2009 BASIC ELECTRICAL AND ELECTRONICS ENGINEERING (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆

2. (a) Explain the following: i. Polarization by selective absorption ii. Polarization by scattering.

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(c) With relevant diagram explain Young’s experiment on the basis of wave theory. [4+4+8]

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(b) Prove that if the angle of incidence corresponds to the Brewster’s angle, then the angle between reflected and refracted beams is 900 . [12+4] 3. (a) Derive Sabine’s formula for reverberation time.

(b) Define the term coefficient of absorption and write short notes on it.

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(c) A hall has dimensions 20 × 15 × 5 m3 . The reverberation time is 3.5 sec. Calculate the total absorption of its surfaces and the average absorption coefficient. [6+6+4] 4. (a) Explain the following typical characteristics of laser: i. coherence ii. divergence and iii. monochromaticity.

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(b) Explain the principle and working of a Ruby laser.

[6+10]

5. (a) What is meant by an acceptance angle for an optical fibre? Obtain mathematical expressions for acceptance angle and numerical aperture (NA).

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(b) An optical fibre has a NA of 0.20 and cladding refractive index of 1.59. Determine the refractive index of core and the acceptance angle for the fibre in water which has a refractive index of 1.33. [10+6]

6. (a) Show that FCC is the most closely packed of the three cubic structures by working out the packing factors. (b) Describe the structure of NaCl.

[10+6]

7. (a) State and explain Bragg’s law. (b) Describe with suitable diagram, the powder method for determination of crystal structure. 1 of 2

Set No. 1

Code No: R05012302

(c) A beam of X-rays of wavelength 0.071 nm is diffracted by (110) plane of rock salt with lattice constant of 0.28 nm. Find the glancing angle for the second order diffraction. [6+6+4] 8. (a) Write in detail the different kinds of crystal imperfections. [10+6]

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(b) Explain the significance of Burgers vector.

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Set No. 2

Code No: R05012302

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I B.Tech Semester Supplimentary Examinations, June 2009 BASIC ELECTRICAL AND ELECTRONICS ENGINEERING (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) What is meant by interference of light? State the fundamental conditions for the production of interference fringes.

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(b) Explain with necessary theory the formation of Newton’s rings and measurement of wavelength of light. [6+10]

i. ii. iii. iv.

Double refraction Optic axis Positive crystals Negative crystals.

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2. (a) Explain in detail, the terms:

(b) What is Brewster’s law? Explain.

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(c) A beam of plane polarized light is converted into a circular polarized light by passing it through a crystal slice of thickness 3 ×10−5 m. Calculate the difference in the refractive indices of the two rays inside the crystal assuming the above thickness to be the minimum value required to produce the observed effect. Wavelength of the light used is 600 nm. [8+4+4] 3. (a) Define the terms of superconductivity:

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i. Critical temperature ii. Critical magnetic field and iii. Critical current.

(b) What are Copper pairs? Explain. (c) Write notes on any four applications of superconductors.

[6+4+6]

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4. (a) Give the various pumping mechanisms that are adopted in lasers. (b) Discuss the essential features of a laser beam. (c) Explain the uses of lasers in various fields.

[6+4+6]

5. (a) Explain the terms ‘numerical aperture’ and ‘acceptance angle’. (b) With the help of a suitable diagram explain the principle, construction and working of an optical fibre as a wave guide. (c) An optical fibre has a core material of refractive index of 1.55 and cladding material of refractive index 1.50. The light is launched into it in air. Calculate its numerical aperture. [6+6+4] 1 of 2

Set No. 2

Code No: R05012302

6. (a) What are the properties of antiferromagnetic materials? (b) What is meant by Neel temperature? (c) Explain how antiferromagnetic materials are different from diamagnetic and para-magnetic materials. [6+4+6] 7. (a) State and explain Bragg’s law.

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(b) Describe with suitable diagram, the powder method for determination of crystal structure.

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(c) A beam of X-rays of wavelength 0.071 nm is diffracted by (110) plane of rock salt with lattice constant of 0.28 nm. Find the glancing angle for the second order diffraction. [6+6+4] 8. (a) Explain Schottky and Frenkel defects with the help of suitable figures.

(b) Derive an expression for the number of Schottky defects in equilibrium at a temperature T.

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(c) The fraction of vacancy sites in a metal is 1 ×10−10 at 500 0 C. What will be the fraction of vacancy sites at 1000 0 C? [6+6+4]

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Set No. 3

Code No: R05012302

1. (a) Describe Fraunhofer diffraction due to N parallel slits.

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I B.Tech Semester Supplimentary Examinations, June 2009 BASIC ELECTRICAL AND ELECTRONICS ENGINEERING (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆

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(b) Describe the action of plane transmission grating in producing diffraction spectrum.

(c) Show that the grating with 5000 lines per cm cannot give a spectrum in the fourth order for a light of wavelength 5890 A.U. [6+6+4]

i. Polarized light ii. Double refraction .

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2. (a) Explain the following:

(b) Calculate the thickness of a quarter wave plate for a monochromatic light of wavelength 600 nm, if the refractive indices of ordinary and extra-ordinary rays in the medium are 1.5442 and 1.5533 respectively. [10+6]

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3. (a) Explain the dependence of super-conducting state of a metal on temperature and strength of the magnetic field in which the metal is placed. (b) Write a note on Meissner effect. (c) What are Cooper pairs?

[6+6+4]

4. (a) Give the various pumping mechanisms that are adopted in lasers. (b) Discuss the essential features of a laser beam. [6+4+6]

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(c) Explain the uses of lasers in various fields.

5. (a) Explain the difference between a step-index fibre and graded index fibre. (b) What are the advantages of an optical fibre communication system over the conventional ones?

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(c) A fibre has the core and cladding refractive indices 1.45 and 1.44 respectively. Find the relative refractive index difference. [6+6+4]

6. (a) Draw the B-H curve for a ferro-magnetic material and identify the retentivity and the coersive field on the curve. (b) What are paramagnetic and diamagnetic materials? (c) An atom contains 10 electrons revolving in a circular path of radius 10−11 m. Assuming homogeneous charge distribution, calculate the orbital dipole moment of the molecule in Bohr magneton. [8+4+4]

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Set No. 3

Code No: R05012302

7. (a) Define Miller indices. Sketch the following atomic planes in a simple cubic structure (010), (110) and (111). (b) Derive an expression for the inter-planar distance in terms of Miller indices for a cubic structure. [6+10] 8. (a) Give an account on the effects of dislocations on the properties of solids. [10+6]

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(b) Explain the significance of Burgers vector.

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Set No. 4

Code No: R05012302

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I B.Tech Semester Supplimentary Examinations, June 2009 BASIC ELECTRICAL AND ELECTRONICS ENGINEERING (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Explain with theory how the refractive index of a liquid can be found using Newton’s rings. [10+6]

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(b) Give the applications of interference of light.

2. (a) Explain why the sky appears blue and red at different times during a day. (b) Discuss how the circular and elliptical polarized lights can be produced.

i. quarter wave plate, ii. half wave plate?

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(c) The refractive index of calcite crystal is 1.658 for ordinary ray and it is 1.486 for extra-ordinary ray. A slice having thickness 0.9 ×10−4 cm is cut from the crystal. For what wavelengths this slice behave as a

[4+6+6]

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3. (a) Explain the dependence of super-conducting state of a metal on temperature and strength of the magnetic field in which the metal is placed. (b) Write a note on Meissner effect. (c) What are Cooper pairs?

[6+6+4]

4. (a) Explain with a neat diagram

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i. absorption ii. spontaneous emission and iii. stimulated emission of radiation. (b) What is population inversion? How it is achieved by optical pumping? [8+8]

5. (a) What are the important features of optical fibres?

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(b) Describe the communication process using optical fibres. (c) Give the uses of fibre optics in different fields.

[6+6+4]

6. (a) Define packing factor. (b) Obtain the packing factor for an FCC structure. (c) Calculate the lattice constant of aluminium having FCC structure from the data given below: Atomic Weight of Al=26.97 gm/mole Density of Al=2.68×106 gm/m3 [4+6+6]

7. (a) Explain Bragg’s law of X-ray diffraction. 1 of 2

Set No. 4

Code No: R05012302

(b) Describe Laue’s method for determination of crystal structure. (c) A beam of X-rays is incident on a NaCl crystal with lattice spacing 0.282 nm. Calculate the wavelength of X-rays if the first order Bragg reflection takes place at a glancing angle of 8o 35′ . Also calculate the maximum order of diffraction possible. [6+6+4]

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8. (a) Explain the various point defects in a crystal.

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(b) Obtain the expression for the equilibrium concentration of vacancies in a solid at a given temperature. [8+8]

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