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Code No: R5100103
I B.Tech (R05) Supplementary Examinations, June 2009 ENGINEERING PHYSICS (Common to Civil Engineering and Mechanical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. (a) Explain the importance of coherent sources in interference phenomenon. (b) Derive an expression for fringe width of bright fringes produced in Young’s double slit experiment. (c) A light source emits light of wavelength 5,100 A.U. is exposed to a double slit. A screen is placed at 2 meters from the slits. Find the distance between the slits, if overall separation of 10 fringes on the screen is 2 cm from its center. [4+8+4] 2. (a) Distinguish between polarized and unpolarized lights. (b) What is Brewster’s law? Explain how this can be used to find the polarizing angles of various crystals. (c) Find the Brewster angle for a glass slab (µ =1.5) immersed in water (µ =4/3). [4+8+4] 3. (a) Describe, in detail, the normal acoustical standards that a concert hall should have. How are they accomplished? (b) The volume of a room is 1500 m3 . The wall area of the room is 260 m2 , the floor area is 140 m2 and the ceiling area is 140 m2 . The average sound absorption co-efficient for wall is 0.03, for the ceiling is 0.80 and for the floor is 0.06. Calculate the average absorption coefficient and the reverberation time. [10+6] 4. (a) What do you understand by population inversion? How it is achieved? (b) Derive the relation between the probabilities of spontaneous emission and stimulated emission in terms of Einstein’s co-efficients. [6+10] 5. (a) Define the relative refractive index difference of an optical fibre. Show how it is related to numerical aperture. (b) Draw the block diagram of an optical fibre communication system and explain the function of each block. [6+10] 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 how the X-ray diffraction can be employed to determine the crystal structure. (b) The distance between (110) planes in a body-centered cubic structure is 0.203 nm. What is the size of the unit cell? What is the radius of the atom? [10+6] 8. (a) Give an account on the effects of dislocations on the properties of solids. (b) Explain the significance of Burgers vector. ?????
[10+6]
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Code No: R5100103
I B.Tech (R05) Supplementary Examinations, June 2009 ENGINEERING PHYSICS (Common to Civil Engineering and Mechanical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. (a) Give the theory of interference and obtain the condition for constructive and destructive interference. (b) Light waves of wavelength 650 nm and 500 nm produce interference fringes on a screen at a distance of 1 m from a double slit of separation 0.5 mm. Find the least distance of a point from the central maximum where bright fringe due to both coincide. [10+6] 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. (c) The refractive index of calcite crystal is 1.658 for ordinary ray and it is 1.486 for extraordinary ray. A slice having thickness 0.9 ×10−4 cm is cut from the crystal. For what wavelengths this slice behave as a i. quarter wave plate, ii. half wave plate?
[4+6+6]
3. (a) Describe Josephson effects and their applications. (b) Write a note on flux quantization. (c) The London penetration depths for lead at temperatures 3 K and 7.1 K are respectively 39.6 nm and 173 nm. Calculate its transition temperature as well as depth at 0 K. [6+4+6] 4. (a) Explain the need of a cavity resonator in a laser. (b) With the help of suitable diagrams, explain the principle, construction and working of a Ruby laser. [6+10] 5. (a) What is the principle of optical fibre communication? Explain. (b) Discuss various types of fibres for light wave communication.
[8+8]
6. (a) Prove that which type of the cubic crystal structure has closest packing of atoms? (b) Derive the relation between the atomic radius and the unit cell dimension of the crystal, mentioned above. [8+8] 7. (a) Sketch the following planes of a cubic unit cell: (001), (120) and (¯211). (b) Explain Bragg’s law of X-ray diffraction. (c) Describe Laue’s method for determination of crystal structure.
[3+5+8]
8. (a) Explain the various point defects in a crystal. (b) Obtain the expression for the equilibrium concentration of vacancies in a solid at a given temperature. [8+8] ?????
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Code No: R5100103 I B.Tech (R05) Supplementary Examinations, June 2009 ENGINEERING PHYSICS (Common to Civil Engineering and Mechanical Engineering) Time: 3 hours
Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
1. (a) With relevant theory explain how radius of curvature of a convex lens be determined by forming Newton’s rings. (b) In Newtons rings system if the diameters of 4th and 6th dark rings are found to be 3.0 mm and 3.6 mm, calculate the wavelength of light used. The radius of curvature of the convex surface of the lens is 0.9 m. [10+6] 2. (a) Discuss the various methods by which polarized light can be produced. (b) A beam of linearly polarized light is changed into circularly polarized by passing it through a 30 µm thick birefringent crystal. Assuming its thickness is minimum and for a light of wavelength 589.3 nm incident on it normally, find the difference of refractive indices of the ordinary and extra-ordinary rays. [10+6] 3. (a) Derive Sabine’s formula for reverberation time. (b) Define the term coefficient of absorption and write short notes on it. (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 need of a cavity resonator in a laser. (b) With the help of suitable diagrams, explain the principle, construction and working of a Ruby laser. [6+10] 5. (a) Distinguish between light propagation in i. step index and ii. graded index optical fibres. (b) Discuss the various advantages of communication with optical fibres over the conventional co-axial cables. (c) Calculate the refractive indices of core and cladding of an optical fibre with a numerical aperture of 0.33 and their fractional difference of refractive indices being 0.02. [6+6+4] 6. (a) Define magnetic flux density, intensity of magnetization, magnetic permeability and magnetic susceptibility. (b) What is meant by magnetic domains? (c) How the magnetic materials are classified? Explain the properties of diamagnetic materials. [6+4+6] 7. (a) Derive Bragg’s law of X-ray diffraction. (b) Describe Bragg’s X-ray spectrometer and explain how Braggs law can be verified. (c) Monochromatic X-rays of λ=1.5 A.U. are incident on a crystal face having an interplanar spacing of 1.6 A.U. Find the highest order for which Braggs reflection maximum can be seen. [6+6+4] 8. (a) Describe edge and screw dislocations. Draw Burgers circuit and slip planes for them. (b) Explain the significance of Burgers vector. ?????
[10+6]
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Code No: R5100103
I B.Tech (R05) Supplementary Examinations, June 2009 ENGINEERING PHYSICS (Common to Civil Engineering and Mechanical Engineering) 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. (b) Give the applications of interference of light.
[10+6]
2. (a) What is meant by polarization of light? (b) Describe an experiment that shows light is not propagated as longitudinal waves. (c) What is plane of vibration?
[6+6+4]
3. (a) Explain superconducting phenomenon. (b) Distinguish between Type-I and Type-II superconductors. (c) Discuss various applications of superconductors.
[6+6+4]
4. (a) With necessary theory and energy level diagram, explain the working of a Helium-Neon gas laser. (b) Mention some important applications of lasers.
[10+6]
5. (a) What is total internal reflection? Discuss its importance in optical fibres. (b) Describe the various types of optical fibres, their advantages and limitations. (c) If the numerical aperture of a fibre is 0.245 with a core refractive index 1.51, calculate the refractive index of cladding as well as acceptance angle. [6+6+4] 6. (a) Explain how the magnetic materials are classified from the atomic point of view. (b) What are the differences between hard and soft magnetic materials. (c) A magnetic material has a magnetization of 3300 ampere / m and flux density of 0.0044 wb / m2 . Calculate the magnetizing force and the relative permeability of the material. [6+6+4] 7. (a) Explain Bragg’s law of X-ray diffraction. (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 350 . Also calculate the maximum order of diffraction possible. [6+6+4] 8. (a) What is Frenkel defect? Explain. (b) Derive an expression for the concentration of Frenkel defects present in a crystal at any temperature. [6+10] ?????