Mechanical Measurement and Metrology

Chapter-1: Mechanical Measurement

1.1        What is measurement?

1.2        Classify measurement system.

1.3        What are the various methods of measurement ? Explain them with examples.

1.4        What are the mode of measurement ? Explain any one with the example.

1.5        Explain the generalized measurement system.

1.6        Explain all the stages of general measurement system.

1.7        What are primary, secondary and tertiary measurements ? Explain with examples.

1.8        Identify the functional elements of bourdon tube pressure gauge and draw the block diagram of the measurement system.

1.9        Explain the functions of signal conditioning stage of measurement system.

1.10      Draw the block diagram of following measurement system.

(i) Mercury in glass theimometer

(ii) Pressure actuated thermometer

1.11      Define the terms (i) measurement, (ii) instrumentation, (iii) instrument, (iv) control.

1.12      Distinguish between direct and indirect method of measurement.

1.13      Draw a block diagram representation of a generalized measurement system. Identify the various elements and point out the functions performed by each element.

1.14      How are instruments classified.

1.15      Give the appropriate examples of daily life on following.

(i) Null output device (ii) Deflection output device (iii) Analog output device.

1.16      Briefly explain contact and non-contact type measurements giving examples.

1.17      What do you mean by characteristics of a measuring instrument ?

1.18      What are static characteristics ? How do they differ from dynamic characteristics ?

1.19      State the dynamic characteristics and explain any five.

1.20      State and explain generalized performance characteristics of instrument with suitable example.

1.21      Define the following terms with respect to one instrument.

(i) Threshold (ii) Resolution (iii) Hysteresis (iv) Dead space.

1.22      Explain following teims giving examples

(i) Precision and accuracy (ii) Threshold and resolution.

1.23      Distinguish between following giving appropriate examples

(i) Hysteresis and dead zone (ii) Range and span

1.24      Explain following characteristics of measuring instalments with suitable illustrations,

(i) Accuracy, (ii) Precision, (iii) Resolution, (iv) Sensitivity, (v) Linearity

1.25      Define following terms:

(i)eiror, (ii) correction, (iii) stiction, (iv) true value.

1.26      Differentiate following terms

(i) Accuracy and precision

(ii) Threshold and resolution

(iii) Hysteresis and dead zone

(iv) Repeatability and reproducibility

1.27      Define following terms:

(i) Speed of response (ii) Dynamic error, (iii) Measuring lag, (iv) Fidelity, (v) Overshoot

1.28      Differentiate between calibration curve and error curve.

1.29      Describe following types of errors and how these can be taken care of

(i) Parallax error, (ii) Backlash error

1.30      Explain following terms stating illustrations:

Accuracy, precision, drift, threshold, and overshoot.

1.31      What means of transducer?

1.32      What are the advantages of electrical transducer compare to mechanical transducers?

1.33      Describe LVDT giving its advantages, limitations and field of applications.

1.34      Describe with a neat sketch “Linear Variable Differential Transformer”. Comment on its applications.

1.35      Describe the operating principle of a piezoelectric transducer with a diagram.

1.36      Discuss the various types of errors in measuring systems.

1.37      How are errors of measurement system classified ?

1.38      Differentiate between systematic error and random error.

1.39      What are systematic errors ? State the common causes of their occurrence.

1.40 What are the different sources of errors in measurements and measuring instruments ?Explain.


Chapter-2: Linear  measurements:

2.1        What is linear measurement ? List the linear measuring instrument according to their accuracy and state their ranges and applications.

2.2        Write short note on engineer steel rule. Name the different type of vernier calipers and state their applications.

2.3        What is least count ? How is it determined in case of vernier caliper ?

2.4        Explain the principle of vernier caliper and its calibration.

2.5        Describe construction, working principle and applications of the vernier height gauge. [June 2010]

2.6        State the types of different micrometers and give their application in metrology.

2.7        Describe with sketch the construction and working of a micrometer. Explain how least count is found and reading is taken. What is zero error ?

2.8        Sketch and describe micrometer stating sources of error.

2.9        Explain the procedure for reading the vernier micrometer.

2.10      State the range and accuracy of the different types of vernier and micrometers.

2.11      Explain the calibration of micrometer screw.

2.12      Compare micrometer and vernier caliper with respect to robustness, ease of reading, accuracy and adjustment of wear with neat sketch.

2.13      Write down the precautions which should be taken while using a micrometer. Explain the use of a telescopic gauge with a neat sketch.

2.14      State the use of (i) Slip gauges, (ii) Dial indicator

2.15      Describe with sketch following stating application

(i) Slip gauges, (ii) Telescopic gauge, [June 2010]

2.16      Briefly explain the Taylor’s principle of gauge design.

2.17      Give the classification of limit gauges and explain with neat sketch the plug gauge.

2.18      With neat sketch explain the ring limit gauge.

2.19      Explain with neat sketch the snap limit gauge.


Chapter-3: Angular and Taper Measurements

3.1        State importance of angle measurements.

3.2        What is the difference between linear and angular measurements ?

3.3        State the various instruments used for measuring angles.

3.4        Explain the construction and working of:

(i) vernier bevel protractor.

(ii) optical bevel protractor.

3.5        Explain the construction and working principle of sine bar.

3.6        Explain how sine bar is used to measure:

(i) angle of component of small size.

(ii) angle of component of large size.

3.7        State the sources of eirors in angular measurement by sine bar.

3.8        State the limitations of sine bar and sketch the various types of sine bar.

3.9        Describe with sketch following stating application:

(i) sine bar, (ii) sine center. [June’10]

3.10      Explain the construction and use of the following with neat sketch.

(i) vernier bevel protractor, and (ii) sine bar [Dec. ’10, 7 Marks]

3.11      Describe with sketch principle, construction and use of Autocollimator.

[June ’10, 7 Marks]

3.12      Sketch sine bar and explain its use to measure angles stating limitations.

3.13      What is clinometer ? Describe how it can be used for measuring and setting of angle and illustrate your answer with neat sketch. [Dec. ’10, 4 Marks]

3.14      Describe spirit level with neat sketch.

3.15      State various types of clinometer. Explain micrometer clinometer with neat sketch.

3.16      Give applications of clinometers.

3.17      Explain how angle of a work piece is measured with the help of angle dekkor and angle gauge. [Dec. ’10, 3 Marks]

3.18      Explain angle dekkor with neat sketch stating applications of it.

3.19      How will you specify sine bar ? Why holes are provided in the body of a sine bar ?

3.20      Explain the method of checking the angle of a taper plug gauge using rollers, micrometer and slip gauges.

3.21      Describe the method of checking the angle of a taper hole.

3.22      Write applications and limitations of angle gauges. [June ‘14,3 Marks]


Chapter-4: Measurement of Force, Torque and Strain

4.1        Explain briefly methods of force measurement.

4.2        What is a load cell ? State various types of load cells and their use and explain any one of them with neat sketch. [G.U., June 2001]

4.3        Write short note on platform scale – a basic method of force measurement. [G.U., June 2006]

4.4        Write short note on the following:

(i) Hydraulic load cell (ii) Strain gauges load cell for force measurement     (iii) Hydraulic load cell

4.5        Describe with sketch proving ring stating its uses and advantages.

4.6        Classify torque and power measuring instruments.

4.7        What are absorption dynamometers ? Explain any one with a neat sketch.

4.8        What are transmission dynamometers ? Explain any one with a neat sketch.

4.9        Write a short note on rope brake dynamometer.

4.10      Describe with sketch eddy current dynamometer stating speed, power limit, advantages and limitations.

4.11      Explain fluid friction (hydraulic) dynamometer stating its advantages, limitations and approximate speed limit and power limit.

4.12      Explain working of a torsion bar dynamometer.

4.13      With neat sketch explain servo-controlled dynamometer.

4.14      Write short note on (i) Unbonded strain gauge, and (ii) Bonded strain gauge

4.15      What is the rosette? Why it is used?

4.16      Briefly explain strain gauge materials.

4.17      Explain with neat sketch the bonded strain gauges.

4.18      What is gauge factor? Explain its importance.

4.19      Why strain gauge temperature compensation required?

4.20      Explain the self temperature compensation in strain gauge.

4.21      With neat sketch explain dummy method of temperature compensation in strain gauge.


Chapter-5: Displacement, velocity/speed and acceleration Measurement

5.1        Explain with neat sketch the resistance potentiometer.

5.2        With neat sketch explain the electro-magnetic transducer for angular speed measurement.

5.3        List the different types of speed measuring devices. Explain with neat sketch the eddy current tachometer.

5.4        How are tachometers classified ?

5.6        Why electrical tachometer preferred to mechanical tachometers ?

5.7        Explain briefly photoelectric tachometer.

5.8        Write short note on the electric tachometer generator.

5.9        Describe working principle of any one type of non-contact type instrument for speed measurement of a rotating machine spindle.

5.10      Explain the principle, working and method of speed measurement using stroboscope stating an illustration.

5.11      What is ‘slip’ in relation to flashing stroboscope ? What is its effect ? Also briefly explain how the speed is measured with stroboscope if the speed to be measured is not in the range of stroboscope.

5.12      Describe calibration process of high speed fan using stroboscope. [July 2010]

5.13      Explain with sketch piezo-electric accelerometer stating advantages, limitations and application.

5.14      Explain with sketch seismic accelerometer.


Chapter-6: Temperature Measurement

6.1        State and explain different temperature scales.

6.2        How are temperature measuring instruments classified ?

6.3        List and explain with sketch types of expansion thermometer stating applications. [June 2010, 7 Marks]

6.4        Describe with sketch bimetal strip thermometer stating salient features.

6.5        Explain the working principle of bimetallic thermometer.

6.6        List important properties which matter in selection of alloy for bimetallic thermometers. What are advantages of bimetallic thermometers in comparison to a mercury-in-glass thermometer ? Why do bimetallic thermometers frequently used a spiral or helix strip rather than just a straight bimetallic strip ?

6.7        Describe with sketch a liquid-in -glass thermometer. Explain its application.

6.8        A mercury in-glass thermometer is said to be calibrated for partial immersion. What does it mean ? List liquids for liquid-in-glass thermometers. What are the measuring range of these liquids ?

6.9        Describe in brief following types of thermometers stating their range of applications.

(i) Liquid filled pressure thermometer.

(ii) Gas filled pressure thermometer.

(iii) Vapour filled pressure thermometer.

6.10      Describe in brief the following types of thermometers stating their range of applications.

(i) Liquid filled pressure thermometer.

(ii) Gas filled pressure thermometer.

6.11      Explain the construction features and basic working of pressure thermometer with suitable sketch.

6.12      Explain briefly the errors in filled system. How are they minimized ?

6.13      Explain the construction features and basic working of pressure thermometer with suitable sketch.

6.14      Explain the principles and types of thermocouples.

6.15      Explain in brief the principle of thermocouple stating an illustrations. [June 2010, 7 Marks]

6.16      Sketch and explain the elements of a thermoelectric pyrometer.

6.17      Explain the thermocouple 1aws.

6.18      Describe thermocouple type temperature measuring devices. List the suitable materials for thermocouples stating their range of applications.

6.19      Describe electrical resistance type thermometers. Write advantages of these over other types of thermometers. What are the ranges of applications of different resistance elementmetals of electrical resistance type thermometers.

6.20      Write short note on following

(i) Thermistors

(ii) Thermocouples

6.21      What is a thermistor ? Explain with neat sketch the construction and working of a thermistor.

6.22      Compare RTD and thermistors as temperature measuring device.

6.23      Explain with a neat sketch total radiation pyrometer. Comment on its range of application.

6.24      Explain with neat sketch optical pyrometers. What are the characteristics of an optical pyrometer.

6.25      Briefly discuss the calibration of theimometer of liquid-in-glass types.

6.26      Describe any one measuring instrument suitable for measuring temperature of molten metal in an electric arc furnace.


Chapter-7: Introduction to Metrology

7.1        What is mean by “metrology” ?

7.2        Explain objectives of metrology. [June ‘14,3 Marks]

7.3        Explain necessity of metrology.

7.4        Why measurement standards are required ?

7.5        Explain the need of standards of measurements in the modern industrial system.

7.6        Explain with sketch: (i) Imperial standard yard, (ii) International prototype metre.

7.7        State the disadvantages of material standard.

7.8        Describe wavelength standard with its advantages.

7.9        Give comparison between material standard and wave length standard.

7.10      Distinguish between Primary, Secondary, Tertiary and working standards of length.

7.11      Explain line and end standards with examples.

7.12      Compare line and end standards.

7.13      Give characteristics of line and end standards.

7.14      State and explain the important elements of measurement.

7.15      State the various methods of measurement and explain any four of them with suitable examples.

7.16      Define (i) Precision, (ii) Accuracy.

7.17      Justify: Precision measurement may not be accurate.

7.18      Distinguish between precision and accuracy.

7.19      State various sources of errors.

7.20      What is the standard temperature for measurement ?

7.21      Describe the effect of the following on precision measurement (i) support, (ii) alignment, (iii) poor contact.

7.22      Write a short note on standardizing organizations.

7.23      Explain the light wave (optical) length standard stating advantages.

7.24      Distinguish between line standard and end standard stating examples.

7.25      Describe with sketch International Prototype Meter (Material Length Standard) stating material composition and limitations.

7.26      Describe with net sketch “Imperial standard yard”. [June ‘ 14,4 Marks]


Chapter-8: Metrology of Gears

8.1        Why inspection of the gear tooth elements is required ?

8.2        Give classification of gears.

8.3        State forms of gear teeth.

8.4        How cycloidal profile for teeth of gear are traced ?

8.5        How involute profile for teeth of gear are traced ?

8.6        Give comparison between involute and cycloidal gears.

8.7        Define following terms related to gear.

(i) Pitch circle, (ii) Pitch circle diameter, (iii) Pressure angle, (i v) Circular pitch.

8.8        Define following terms related to gear:

(i) Module, (ii) Diametral pitch, (iii) Addendum, (iv)Dedendum, (v)Face, (vi) Flank.

8.9        State the elements of the spur gear which are checked for accuracy of the gear.

8.10      Explain tooth to tooth pitch measurement method with neat sketch.

8.11      Explain profile checking by using involute measuring machine with neat sketch.

8.12      State methods for measuring tooth thickness.

8.13      Describe with sketch the construction and use of Gear Tooth vernier Caliper. How is the gear tooth thickness at PCD measured ? [June ‘ 10, 7 Marks]

8.14      Sketch and explain the methods to measure gear tooth thickness at pitch circle diameter.

8.15      Explain different methods of checking tooth thickness of gear giving suitability of each one critically.

8.16      Write short notes on the Parkinson gear tester.

8.17      Explain David Brown tangent comparator with neat sketch.

8.18      Explain Base tangent method for measuring gear tooth thickness.

8.19      Explain constant chord method for measuring gear tooth thickness with neat sketch.

8.20      Explain measurement of gear tooth thickness by measurement over rollers.

8.21      Explain the method of measuring a chordal thickness of a gear tooth.

8.22      Explain principle and working of Parkinson’s gear tester with neat sketch.

8.23      Explain following gear eirors:

(i) Profile error, (ii) Pitch error, (iii) Eirors in pressure angle, (iv) Tooth thickness error.

8.24      List the various elements to be checked for the accuracy of gear and describe any two. [Dec. ’10, 4 Marks]

8.25      Explain Parkinson gear tester with neat sketch. [June ’14, Dec. ’10]


Chapter-9: Screw Thread Measurement

9.1        Explain the functions of screw thread.

9.2        What is the pitch of screw thread ? State it’s significance.

9.3        Classify screw threads.

9.4        What do you understand by single start and multi-start threads ?

9.5        State various elements of screw thread.

9.6        Define following terms:

(i) Effective or pitch diameter, (ii)Lead, (iii) Pitch, (iv) Crest.

9.7        State various types of transmission threads.

9.8        Describe construction, principle of working and applications of a Bench micrometer.

9.9        How the minor diameter of the external screw thread is measured ?

9.10      State the methods for measurement of effective diameter of external screw thread.

9.11      Explain one wire method for measurement of effective diameter of screw thread stating limitation.

9.12      What is an effective diameter of threads ? State its significance. Explain with sketch measurement of effective diameter by two wire method stating limitation. [June ’10]

9.13      Explain the three wire method to measure the effective diameter of given screw thread with neat sketch. [June ’14, 7 Marks]

9.14      Derive the expression for best wire size.

9.15      Which are the errors we have to consider while measuring effective diameter using wires ? Explain these errors.

9.16      Explain measurement of thread angle by vernier protractor with neat sketch.

9.17      State the methods for measurement of pitch. Explain pitch measuring machine with neat sketch.

9.18      Explain effects of pitch errors in screw threads.

9.19      How the major and minor diameters of internal screw threads are measured ?

9.20      How effective diameter of internal screw threads are measured ?

9.21      Explain pitch measurement of internal screw threads with neat sketch.

9.22      How gauging is differ from measuring ? Explain gauging of screw thread.

9.23      Explain following pitch errors:

(i) progressi ve error,

(ii) periodic error,

(iii) drunken error,

(iv) irregular error.

9.24      Explain the measurement of effective diameter for internal screw threads with neat sketch. [June ‘14,4 Marks]


Chapter-10: Metrology of Surface Finish

10.1      State the properties which are influenced by the surface finish.

10.2      State the factors on which surface finish is dependent.

10.3      Define the term : (i) Primary texture, (ii) secondary texture.

10.4      Classify geometrical irregularities.

10.5      Define the following elements of surface texture:

(i) Roughness, (ii) Waviness, (iii) Flaws, (iv)Lay, (v) Sampling length, (vi) Mean line profile.

10.6      Explain surface texture and elements of surface roughness. [June ‘10,7 Marks]

10.7      Explain the following terms used in surface finish :

(i) Roughness, (ii) Waviness, (iii) Effective profile, (iv) Centreline of profile and (v) Lay [Dec. ’10, 3 Marks]

10.8      State various comparison methods for surface inspection.

10.9      Explain following comparison methods for surface inspection.

(i) Visual inspection, (ii) Scratch inspection, (iii) Microscopic inspection, (iv) Wallace surface dynamometer.

10.10    Explain the parameters used in surface roughness measurement.

10.11    Sketch and describe the construction and working of Tomilson surface roughness tester. [Dec. ’14, June ’14]

10.12    Explain why surface assessment is necessary for critically mating components. How the surface roughness is represented ?

10.13    Draw neat sketch of ‘Taly-surf and explain its working principle.

10.14    Explain profilometer with neat sketch.

10.15    Explain profilograph with neat sketch.

10.16    Define the following with reference to surface texture:

(i) Peak to valley height, (ii) C.L.A. (iii)R.M.S.

10.17    Explain various adverse effects of poor surface finish.

10.18    Explain Pneumatic method for measuring surface roughness.

10.19    Explain light interference microscope.

10.20    Explain principle of Mecrin instrument with neat sketch.

10.21    Explain surface texture and elements of surface roughness. [June ‘14,7 Marks]


Chapter-11: Comparators

11.1      Describe in detail the application of comparator.

11.2      Give detail classification of comparator.

11.3      Explain with neat sketch the construction and working of Johansson Mikrokator.

11.4      How magnification is achieved in (i) Sigma comparator and (ii) Optical comparator?

11.5      Describe with sketch the construction and working of sigma comparator. [June 2010]

11.6      Sketch and describe an optical comparator stating advantages and limitations.

11.7      Give characteristics features of comparator and explain relative merits of amplifying devices used in different types of comparators.

11.8      Write short note on (i) Mechanical comparator, and (ii) Dial indicator.

11.9      What are the important features of a good comparator ?

11.10    Differentiate between mechanical and pneumatic comparators.

11.11    What are the advantages of electrical and electronic comparator ?

11.12    Explain with neat sketch construction and working of electrical comparator.

11.13    Give brief comparisons of different types of comparators.

11.14    Give comparison between the measuring instrument and the comparator.


Chapter-12: Miscellaneous Metrology

12.1      With the help of neat sketch, explain the working principle of a laser transducer system.

12.2      Why double-frequency radiation source is needed in a laser transducer?

12.3      What is coordinate measuring machine? Explain different configurations of CMM.

12.4      Explain operation of CMM.

12.5      State the applications of CMM.

12.6      Explain the optical system and working principle of a profile projector.

12.7      What is optical square? Describe with the help of a neat sketch the optical test for squareness?

12.8      Describe tool maker’s microscope with neat sketch.

12.9.     What is the importance of interferometry in field of metrology ?

12.10    Describe optical flat. How it is used in checking flatness ?

12.11    Explain surface contour test.

12.12    How parallelism can be checked by using optical flat ?

12.13    Explain with neat sketch the working of any one type of interferometer.

12.14    State disadvantages of optical Hat.

12.15    Describe N.P.L. flatness interferometer with neat sketch.

12.16    How parallelism can be checked by N.P.L. flatness interferometer ?

12.17    Explain Fitter N.P.L. gauge interferometer with neat sketch.

12.18    Describe opto-electronics measurements with neat sketch.



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