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Previous Year Exam Questions of Electrical Measurement and Instrumentation of SPPU - EMI by Kritika rai

  • Electrical Measurement and Instrumentation - EMI
  • 2012
  • PYQ
  • Pune University - SPPU
  • Electrical Engineering
  • B.Tech
  • 4 Views
  • Uploaded 4 months ago
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Total No. of Questions—12] [Total No. of Printed Pages—4+1 Seat No. [4262]-142 S.E. (Electrical) (I Sem.) EXAMINATION, 2012 MATERIAL SCIENCE (2008 PATTERN) Time : Three Hours N.B. :— (i) Maximum Marks : 100 Answer three questions from Section I and three questions from Section II. (ii) Answers to the two Sections should be written in separate answer-books. (iii) Neat diagrams must be drawn wherever necessary. (iv) Figures to the right indicate full marks. (v) You are advised to attempt not more than 6 questions. (vi) Your answers will be valued as a whole. (vii) Use of logarithmic tables, slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed. (viii) Assume suitable data, if necessary. Physical Constants : (1) Angstrom Unit (AU) = 1 × 10–10 metres. (2) Dielectric constant of free space (∈0) = 8.85 × 10–12 farad/ metre. P.T.O.

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(3) Electron volt (eV) = 1.602 × 10–19 Joules. (4) Permeability of free space (µ0) = 4π × 10–7. (5) Mass of electron (m) = 9.107 × 10–31 kg. (6) Mass of proton (mp) = 1.627 × 10–27 kg. (7) Velocity of light (c) = 3 × 108 metre/second. (8) Charge on electron (e) = 1.601 × 10–19 coulomb. (9) Debye unit = 3.33 × 10–30 coulomb-metre. (10) Boltzmann’s constant (k) = 1.38 × 10–23 Joule degree–1. SECTION I 1. (a) Explain orientation polarization in detail. How is it different than ionic polarization ? (b) [9] Differentiate between photoconductive and photoemissive cells. [9] Or 2. (a) Write different materials used for photovoltaic material. Describe its construction and working principle. (b) Differentiate between piezoelectric, ferroelectric and pyroelectric materials. 3. [9] Write down properties and applications of the following : (i) [4262]-142 [9] Paper Press Board 2 [16]

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(ii) Sf6 gas (iii) Ceramics (iv) Mica and Asbestos. Or 4. (a) How does breakdown occur in vacuum ? Explain by using any one (b) 5. (a) theory. [8] Define : [8] (i) breakdown voltage; (ii) breakdown strength; (iii) Primary ionization; and (iv) Secondary ionization. Differentiate between Soft Magnetic Materials and Hard Magnetic Materials. (b) [8] Calculate Hysteresis loss in a specimen of iron subjected to a magnetization of 60 Hz. The weight of specimen is 50 kg and its density is 8000 kg/m3. Hysteresis loop area is equivalent 250 J/m3. What will be hysteresis loss of specimen of 40 Hz ? [4262]-142 [8] 3 P.T.O.

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Or 6. Explain with properties and applications Diamagnetism, Para- magnetism, Ferro-magnetism and Ferri-magnetism. [16] SECTION II 7. (a) Write a short note on thermocouple. [4] (b) What is a bimetal ? Give [4] (c) A filament of a 230 V, 60 W lamp is to be constructed. The two applications of bimetal. temperature of the filament is to be 1500°C at 60 W. Resistivity of the filament material at 30°C is 5.3 × 10–6 Ω-cm and temperature co-efficient α30 = 0.005/°C. Calculate the length of the filament at 30°C if its diameter at 30°C is 0.025 mm. [8] Or 8. (a) Describe the groups into which the materials as electric conductors are divided. [6] (b) Write a short note on superconductivity. [6] (c) Give the electrical properties and applications of Nichrome and Tungsten. 9. (a) [4] What are molecular machines ? Why are molecular machines currently been extensively investigated ? What are different possible applications of molecular machines ? [4262]-142 4 [8]

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