Metrology Important Questions for R23 JNTU Students
Metrology is one of the most scoring subjects in mechanical engineering. Whether you are preparing for diploma, B.Tech, or competitive exams, understanding metrology makes your measurement concepts strong and boosts accuracy in numerical problems.
This blog gives you unit-wise metrology important questions, including theory questions (20–25 per unit) and numerical problems (10 per unit).
All questions are simple, clear, and exam-oriented.
Let’s get started.
Metrology Important Questions for R23 JNTU Students (Unit-Wise)
Unit 1: Basics of Metrology & Measurement Systems
Key Theory Questions
What is metrology? Explain its role in manufacturing.
Objectives of metrology in industry.
Different types of measurement systems.
Accuracy vs Precision – explain with examples.
Define repeatability and reproducibility.
What is traceability in metrology? Why is it important?
Explain different types of measurement standards.
What is calibration? Why do we calibrate instruments?
Types of measurement errors.
Explain random and systematic errors.
What is parallax error?
Environmental effects in metrology.
What is measurement uncertainty?
Performance characteristics of measuring instruments.
What is resolution?
Explain sensitivity and hysteresis.
What are primary, secondary and tertiary standards?
What is static and dynamic calibration?
Explain line standard and end standard.
Define least count and give examples.
What is drift in measuring instruments?
Difference between contact and non-contact measurement.
Why is metrology important for quality control?
Explain interchangeable manufacturing.
What are the main components of a measuring system?
Numerical Focus Question
Calculate uncertainty when accuracy is ±0.02 mm.
Percentage error when true value = 20 mm, observed = 19.96 mm.
Precision index from repeated readings.
Overall error combining systematic and random error.
Temperature error in steel due to expansion.
Calculate resolution for 100-division instrument.
Sensitivity calculation from output/input data.
Find total uncertainty for given error components.
Drift over time calculation.
Percentage accuracy of a measuring device.
Unit 2: Linear Measurement
Key Theory Questions
What is linear metrology?
Explain slip gauges and wringing.
Classification of slip gauges.
Working principle of Vernier caliper.
Errors in Vernier caliper measurement.
Principle of micrometer screw gauge.
Zero error in micrometer.
What is a comparator?
Types of comparators.
Explain Johansson gauge blocks.
Explain sine bar and its applications.
What are angle blocks?
What is a profile projector?
Working of dial indicator.
What is a universal measuring machine?
Straightness and flatness measurement.
Principle of CMM.
Applications of CMM in metrology.
What are slip gauge accessories?
Explain taper measurement.
Differences between line and end standards.
Explain ring gauges and plug gauges.
What is a height gauge?
What is a bench micrometer?
Applications of comparators in industry.
Numerical Focus Question
Find slip gauge combination for 48.62 mm.
Sine bar angle calculation.
Vernier least count and error calculation.
Micrometer zero correction.
Taper angle numerical.
Temperature error in slip gauge.
Dial indicator reading calculation.
CMM coordinate reading problem.
GO/NO-GO gauge acceptance problem.
- Linear tolerance numerical.
Unit 3: Angular Measurement
Key Theory Questions
Define angular metrology.
Types of angle measuring instruments.
Bevel protractor construction and working.
Autocollimator principle.
What is a sine center?
Explain angle gauges.
Use of precision spirit level.
Working of polygon for angle measurement.
What is a clinometer?
Angle encoders and applications.
Optical square principle.
What is angular calibration?
Errors in angular measurement.
Taper angle measurement.
Universal bevel protractor.
Use of autocollimator in straightness measurement.
Angle blocks and uses.
Rotary encoder principle.
Angle measuring microscope.
Angular deviation meaning.
Explain minimum deviation method.
Laser-based angular measurement.
Define angular accuracy.
Angular interferometry.
Applications of angle gauges.
Numerical Focus Question
Calculate angle using a sine bar.
Taper angle numerical based on diameter change.
Autocollimator reading problem.
Angular deviation calculation.
Polygon-based angle measurement.
Rotary encoder pulse-based angle calculation.
Precision level angle output.
Clinometer angle reading.
Slope angle calculation.
Correction in angular measurement.
Unit 4: Limits, Fits, Tolerances & Gauges
Key Theory Questions
Define tolerance in metrology.
What are clearance, interference and transition fits?
What is unilateral tolerance?
What is bilateral tolerance?
Explain Taylor’s principle of GO/NO-GO gauges.
Tolerance grade and IT grade.
Hole basis and shaft basis system.
Allowance and its importance.
Maximum material condition (MMC).
Least material condition (LMC).
Gauge tolerance and wear allowance.
Compound limit gauges.
Multi-GO gauges.
IS system of limits and fits.
Tolerance stack-up meaning.
True position tolerance.
Geometrical tolerances.
Roundness and cylindricity tolerance.
Straightness tolerance.
Flatness tolerance.
Profile tolerance.
Concentricity tolerance.
Datum and feature in GD&T.
Virtual condition meaning.
Why gauges are preferred in mass production?
Numerical Focus Question
Fit type based on upper and lower limits.
Tolerance calculation.
Allowance numerical.
Maximum and minimum size problem.
Hole basis fit numerical.
Shaft basis fit numerical.
IT grade calculation.
Wear allowance numerical.
Gauge maker’s tolerance.
GD&T true position numerical.
Unit 5: Advanced Metrology
Key Theory Questions
What is interferometry?
Laser interferometer principle.
Surface roughness parameters (Ra, Rz, Rq).
What is a profilometer?
Roundness measuring machine (Talyrond).
Contact vs non-contact measurement.
Basics of coordinate metrology.
Types of CMM.
Probes used in CMM.
Surface texture metrology.
Optical flats and applications.
Interference fringe patterns.
CNC inspection systems.
Nanometrology introduction.
Use of AFM in metrology.
White-light interferometry.
Digitizers and scanners.
Laser scanning metrology.
Ultrasonic measurement.
X-ray CT metrology.
Waviness and lay.
3D measurement systems.
Holography in metrology.
Surface finish measurement methods.
Precision form measurement.
Numerical Focus Question
Ra roughness calculation.
Interference fringe counting.
Laser wavelength displacement.
Roundness error numerical.
Surface finish average height.
Coordinate tolerance numerical.
Fringe spacing calculation.
Waviness measurement.
Flatness variation.
Profilometer reading numerical.
Preparation Tips for Metrology (R23)
Start with basics – first understand accuracy, precision, errors, and calibration.
Revise definitions daily – many metrology important questions come from simple definitions.
Practice instrument working – focus on Vernier, micrometer, slip gauges, comparators, and sine bar.
Draw simple diagrams – instruments and gauges are easy marks in exams.
Solve one numerical from each unit every day to build confidence.
Focus on Limits, Fits & Tolerances – this unit has the highest weightage.
Use small notes or flashcards for tolerance terms, gauges, and measurement standards.
Practice slip gauge combinations – this is a very common numerical topic.
Solve previous papers to understand repeated metrology important questions.
Revise for 15–20 minutes daily during the last week — short but consistent revision works best.
Conclusion
Metrology is one of the most important and scoring subjects for R23 mechanical students. When you understand the basics, practice instrument working, and solve a few numerical problems, the subject becomes very easy to learn. The unit-wise metrology important questions given in this blog help you focus on the exact topics that commonly appear in exams.
By following the simple preparation tips, revising key definitions, and practicing tolerances, fits, gauges, and measurement principles, you can score high marks with confidence. Consistent revision and understanding the concepts—not memorizing—are the keys to mastering metrology.
