MULTIPLE-CHOICE QUESTIONS
1. When a set of readings of a measurement has a wide range, it indicates
(a) high precision (c) low precision
(b) high accuracy (d) low accuracy
2. The difference between the lower and higher values that an instrument is able to measure is called
(a) accuracy (c) range
(b) sensitivity (d) error
3. When determining the uncertainty for a particular measurement device, the common uncertainty factors that should be included are
(a) errors in the measurement technique and method
(b) random variability of the measurement process
(c) technician’s error
(d) all of these
4. The aim of calibration is to
(a) meet customer requirement
(b) detect deterioration of accuracy
(c) comply with ISO 9000 standard requirements
(d) practise measurement procedures
5. Which of the following defines parallax error?
(a) Same as observational error
(b) Apparent shift of an object when the position of the observer is altered
(c) Error caused by the distance between the scale and the measured feature
(d) Mean of the values of measurements when the object is observed from the right and from the left
6. The best way to eliminate parallax error is to
(a) use a magnifying glass while taking measurements
(b) use a mirror behind the readout pointer or indicator
(c) centre the scale along the measured feature
(d) take consistent measurements from one side only
7. Which of the following errors is eliminated or minimized by zero setting adjustment on a dial indicator?
(a) Parallax error (c) Alignment error
(b) Inherent error (d) Computational error
8. The best standard characteristic when calibrating an instrument for production inspection is
(a) ten times the accuracy
(b) new and seldom used since calibration
(c) permanently assigned to this particular instrument
(d) using a standard similar in size, shape, and material, with part being measured
9. Interpretation of repeated measurement results on the same feature is considered the instrument’s
(a) accuracy (c) range
(b) precision (d) sensitivity
10. When a steel rule is used, which of the following is the source of measurement uncertainty?
(a) Inherent instrument error, temperature error, and manipulative error
(b) Attachment error, manipulative error, and temperature error
(c) Attachment error, bias, and inherent instrument error
(d) Inherent instrument error, manipulative error, and observational error
11. Accuracy is defined as
(a) a measure of how often an experimental value can be repeated
(b) the closeness of a measured value to the real value
(c) the number of significant figures used in a measurement
(d) none of these
12. Conformity of a physical quantity to the national standard of measurement is known as
(a) calibration (c) traceability
(b) sensitivity (d) repeatability
13. Systematic errors are
(a) controllable errors
(b) random errors
(c) uncontrollable errors
(d) none of these
14. When a series of repeated measurements that are made on a component under similar conditions are plotted, it follows
(a) log-normal distribution
(b) Weibull distribution
(c) binomial distribution
(d) Gaussian distribution
15. Random errors can be assessed
(a) experimentally
(b) by performing sensitivity analysis
(c) statistically
(d) empirically
REVIEW QUESTIONS
1. Define metrology. Explain the significance of metrology.
2. Differentiate between sensitivity and consistency.
3. Define measurand and comparator.
4. Briefly explain legal and deterministic metrology.
5. Distinguish between direct and indirect measurements. Give two examples of each.
6. Describe any five methods of measurement.
7. Define the following:
(a) Range of measurement
(b) Sensitivity
(c) Consistency
(d) Repeatability
(e) Calibration
(f) Traceability
8. Differentiate between accuracy and precision.
9. What are the possible sources of errors in measurements? Briefly explain them.
10. Discuss the need for inspection.
11. Explain the important elements of measurements.
12. Differentiate between systematic and random errors.
13. Discuss the relationship between accuracy and cost.
14. List the objectives of metrology.
15. Discuss the different reasons for the occurrence of systematic errors.
Answers to Multiple-choice Questions
1. (a) 2. (c) 3. (d) 4. (b) 5. (b) 6. (b) 7. (c) 8. (a)
9. (b) 10. (d) 11. (b) 12. (c) 13. (a) 14. (d) 15. (c)
