Mechanical Measurement and Metrology - Jun 2014

Mechanical Engg. (Semester 4)

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 (a) Briefly explain: i) International prototype meter ii)Reference standard iii)Wringing phenomenon iv) Significance of wevlength standard.(8 marks) 1 (b) What are Airy points? Explain in detail.(4 marks) 1 (b) What are Airy point? Explain in detail.(4 marks) 1 (c) Using NPL method, derive equation for calibrating end standard from line standards.(8 marks) 1 (c) Using NPL method, derived equation for calibrating end standards from line standards.(8 marks) 2 (a) What are the concepts of interchangeability and selective assembly? Which is advantageous?(6 marks) 2 (a) What are the concepts of interchange ability and selective assembly? Which is advantages?(6 marks) 2 (b) Briefly explain:
i) Go-gauges, ii) NO-GO gauges, iii) Gauge tolerance and wear allowance.(6 marks) 2 (b) Briefly explain : i) Go-gauges, ii) NO-GO gauges, iii) Gauge to clearance 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 D^0.34 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) 2 (c) Determine the to tolerance on the hole and shaft for a fit designated by 50H7g6; diameter step 50 to 80 mm; fundamental deviation for shaft =-2.5D⁰³⁴ in micron; 1T6=10i and IT7=16i, i=$$0.45\sqrt[3]{D+0.001D}$$ in micron. State the actual maximum and minimum sizes 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 (a) What are comparators? How do they different from measuring instruments?(6 marks) 3 (b) Explain the principle of sine bar.(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) 3 (c) Explain with the 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 (a) What is the principle of interferometry? How is it adopted in optional interferometer?(6 marks) 4 (b) Derive an expression for the chordal tooth thickness of gear.(6 marks) 4 (b) Derive an expression for the cherdal tooth thickness of gear.(6 marks) 4 (c) Explain 3-wire method of measuring effective diameter of screw thread.(8 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 (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 (b) Explain the three stage 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) 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 (a) What is the necessity of modifying devices? What are the advantages of electrical modifying devices?(6 marks) 6 (b) Explain with a neat sketch, ballast circuit diagram.(6 marks) 6 (c) With a block diagram, explain the working of an x-y plotter.(8 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 (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 (b) What are the methods of force measurement? Give example.(6 marks) 7 (c) Explain with a neat sketch proxy brake dynamometer.(8 marks) 7 (c) Expalin with a neat sketch prony break dynamometer(8 marks) 8 (a) Explain the working principles of radiation pyrometer and thermocouple.(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) 8 (b) Briefly explain : i) Strain gauge material; ii) strain gauge factor, iii) Thermocouple material.(12 marks)