Question Paper: Mechanical Measurement and Metrology : Question Paper Jun 2014 - Mechanical Engineering (Semester 3) | Visveswaraya Technological University (VTU)
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## Mechanical Measurement and Metrology - Jun 2014

### Mechanical Engg. (Semester 3)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
1 (a) Briefly explain:
i) International prototype metre
ii) Reference standard
iii) Wringing phenomenon
iv) Significance of wavelength standard.
(8 marks)
1 (b) What are Airy points? Explain in detail.(4 marks) 1 (c) Using NPL method, derive equation for calibrating end standard from line standards.(8 marks) 2 (a) What are the concepts of interchangeability and selective assembly? Which is advantageous?(6 marks) 2 (b) Briefly explain:
i) Go-gauges, ii) NO-GO gauges, iii) Gauge tolerance and wear allowance.
(6 marks)
2 (c) Determine the tolerance on the hold and shaft for a fit designated by 50H7g6, diameter step 50 to 80 mm; fundamental deviation for shaft=-2.5 D0.34 in micron; 1T6=10i and IT7=16i; i=0.45 $$\sqrt[3]{D} +0.001D$$ in micron. State the actual maximum and minimum size of the hole and shaft and maximum and minimum clearances.(8 marks) 3 (a) What are comparators? How do they differ from measuring instruments?(6 marks) 3 (b) Explain the principle of sine bar.(6 marks) 3 (c) Explain with sketch, the construction and working of LVDT.(8 marks) 4 (a) What is the principle of interferometry? How is it adopted in optical interferometer?(6 marks) 4 (b) Derive an expression for the chordal tooth thickness of gear.(6 marks) 4 (c) Explain 3-wire method of measuring effective diameter of screw thread.(8 marks) 5 (a) What is the significance of measurement?(4 marks) 5 (b) Explain the three stages of generalized measuring method using any one example.(8 marks) 5 (c) Differentiate:
i) Sensor and transducer
ii) Primary and secondary transducer
iii) Accuracy and sensitivity
iv) Error and correction
(8 marks)
6 (a) What is the necessity of modifying devices? What are the advantages of electrical modifying devices?(6 marks) 6 (c) With a block diagram, explain the working of an x-y plotter.(8 marks) 7 (a) Briefly explain how pressure can be measured with elastic transducer.(6 marks) 7 (b) What are the methods of force measurement? Give examples.(6 marks) 7 (c) Explain with a neat sketch prony brake dynamometer.(8 marks) 8 (a) Explain the working principles of radiation pyrometer and thermocouple.(8 marks) 8 (b) Briefly explain: i) Strain gauge material; ii) Strain gauge factor; iii) Thermocouple material.(12 marks)