Mechanical Measurement and Metrology - Jun 2015

Mechanical Engineering (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) Define the term metrology. List and explain the objectives of metrology.(10 marks) 1 (b) Explain with neat sketch: i) Imperial standard yard
ii) International prototype meter.(10 marks) 2 (a) Determine the tolerances on the hold and the shaft for a precision running bit designated by 50H₇G₆ Given:
i) 50mm lies between 30-50mm
ii) i(microns)=0.45(D)¹¹³+0.001D
iii) Fundamental deviation for 'g' shift= -2.5 D^0.34
iv) IT₇= 16i
v) IT₆=10i.(12 marks) 2 (b) Explain with neat sketches hole basis system and shaft basis system.(8 marks) 3 (a) Explain with a neat sketch the working of sigma comparator.(10 marks) 3 (b) Explain with a neat sketch the construction and working of a LVDT.(10 marks) 4 (a) Explain with a neat sketch, Auto collimetor.(10 marks) 4 (b) What are the various characteristics that you would measure in a crew thread? Explain 3 wire method of measuring effective diameter of screw thread.(10 marks) 5 (a) With a block diagram, explain generalized measuring system with examples.(10 marks) 5 (b) Define the following terms: i) Calibration ii) Sensitivity iii) Hysteresis iv) Repeatability v) Accuracy.(10 marks) 6 (a) With a neat sketch, explain the working principle of a CRO.(10 marks) 6 (b) With a neat sketch, explain X-Y plotter and list the advantages.(10 marks) 7 (a) With a neat sketch, explain 'Hydraulic Dynomometer'.(10 marks) 7 (b) With a neat sketch McLeod gauge.(10 marks) 8 (a) What is a Thermocouple? State the laws of Thermocuple.(8 marks) 8 (b) Sketch and explain the working principle of optical pyrometer.(12 marks)