This set of Engineering Metrology Assessment Questions and Answers focuses on “Type B Evaluation of Standard Uncertainty”.
1. Which type of uncertainty is evaluated in Type-B Evaluation?
a) When observations are taken under same conditions
b) When information has possible variability of input variables
c) When Information is present non continuous manner
d) When information is available and is used as it is without any judgement
Explanation: The standard uncertainty where the available information is present with a possible variability of input variables is evaluated by Type-B method of evaluation. For making Type-B evaluations critical thinking, intellectual honesty and professional skill are required.
2. Type-B method is a type of which evaluation approach?
a) Gaussian approach
b) Triangular distribution approach
c) U shaped distribution approach
d) Modern approach
Explanation: Type-B method is a part of modern approach, it’s another part is Type-A method. Type-B evaluation of uncertainty use manufacturer’s specifications like previous measurement data for material or measuring instrument.
3. What is the coverage factor in a Type-B method?
a) Any numerical value only
b) A multiple of sigma only
c) A numerical value or multiple of sigma
d) Always equal to one
Explanation: The coverage factor is specified either as one numerical value or may be stated at a multiple of sigma. The uncertainty or we can say standard can be obtained by the dividing the given value by the multiple.
4. What value of uncertainty cannot be taken in a Type-B method?
a) Standard uncertainty without certificate
b) Resultant of previous value
c) Evaluated on the basis of experience
d) Reference value from the literature
Explanation: The value of uncertainty may be taken from a reference value from the literature, a resultant value of a previous measurement, using the standard uncertainty for which calibration certificate is available or could be evaluated on the basis of experience.
5. If calibration certificate state the uncertainty at Xσ (X is numerical value) and quoted uncertainty is N, then what is the value of standard uncertainty?
Explanation: The standard uncertainty will be obtained by dividing the given value by the multiple. For example, if a calibration certificate states the uncertainty at 5a, the standard uncertainty is then simply, quoted uncertainty/5.
6. When is rectangular distribution is used in Type-B evaluation method?
a) When value of measurand is equal to upper limit
b) When value of measurand is equal to lower limit
c) When measurand lies anywhere within the limits
d) When no limits can be determined
Explanation: Rectangular distribution is used when the limits can be determined and the value of the measurand is equally likely to lie anywhere within the limits.
7. When is triangular distribution is used in a Type-B method?
a) When most values are near the origin
b) When most values are near the right most position of distribution
c) When most values are near the left most position of distribution
d) When most values are near the centre of distribution
Explanation: Triangular distribution of Type-B evaluation is used when it is known that most of the values used are more likely to be near the centre of the distribution, rather than at the extreme limits.
8. What is the sensitivity coefficient?
a) It describes how sensitive the input data is
b) It describes to what extent output data is influenced with variation in input data
c) It describes to what extent input can change
d) It describes to what extent input data is influenced with variation in the number of observations
Explanation: The sensitivity coefficient describes to what extent the output estimate is influenced by variation of the input estimate. The sensitivity coefficient can be calculated by varying the quantity over range of uncertainty list and measuring its influence on the measurand.
9. Which of the following is not treated as Type-B uncertainty?
b) Common Mode Voltage
Explanation: Resolution, Scale Size and Quantization, Hysteresis, Common Mode Voltage, Installation, Nonlinearity or Linearity, Spatial Variation, Loading uncertainties, Sensitivity and Zero offset, these all are Type-B uncertainties.
10. Which distribution is related to U-probability distribution of Type-B evaluation of uncertainty?
a) Arcsin distribution
b) Binomial distribution
c) Poisson distribution
d) Bernoulli distribution
Explanation: U-probability distribution of Type-B evaluation method of uncertainty is used when the values are at extreme limits and values are least at mean for example Arcsin distribution. Standard uncertainty = a/√2.
Sanfoundry Global Education & Learning Series – Engineering Metrology.
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