Measurement and Instrumentation Error MCQ || Measurement and Instrumentation Error Questions and Answers

Measurement and Instrumentation Error MCQ


1. Which of the following is caused by careless handling?

  1. Systematic error
  2. Gross error
  3. Random error
  4. None of the mentioned

Answer:2. Gross error


Gross errors are mistakes that make the measurement very far off of the known/accepted value. Gross errors are caused by experimenter carelessness or equipment failure.

Gross errors can be avoided by using two suitable measures, and they are written below:

  • Proper care should be taken in reading, and recording the data. Also, the calculation of error should be done accurately.
  • By increasing the number of experimenters, we can reduce the gross errors. If each experimenter takes different readings at different points, then by taking the average of more readings we can reduce the gross errors


2. A meter reads 125 V and the true value of the voltage is 125.5 V. Find the static error of the instrument.

  1. 125/0.5 V
  2. 125 V
  3. 0.5 V
  4. 0.5 / 125 V

Answer.3. 0.5 V


Static error (E) = Am – At

Am = Measured value

At = True value


Am = 125 V, At = 125.5 V

∴ Static error (E) = 125 – 125.5

E = 0.5 V


3.  _______  error will remain in a system even if we remove all systematic errors.

  1. Gross Error
  2. Random Error
  3. Observational Error
  4. Instrumentational Error

Answer.2. Random Error


Random errors are those errors, which occur irregularly and hence are random. The random error causes one measurement to differ slightly from the next. It comes from unpredictable changes during an experiment.

Random errors will remain in a system even if we remove all systematic errors. Random errors are also known as residual errors.


4. The difference between the indicated value and the true value of a quantity is:

  1. Gross error
  2. Absolute error
  3. Dynamic error
  4. Relative error

Answer.2. Absolute error


The difference between the indicated or measured value and the true or actual value is called absolute error. Also known as a static error.

Absolute error (ε) = Am – At


Am =  measured or indicated value

At = true or actual value


5. Which of the following is not a fundamental quantity?

  1. Length
  2. Angle
  3. Time
  4. Luminous intensity

Answer.2. Angle


The Fundamental Quantity is an independent Physical Quantity that is not possible to express in other Physical Quantity.

Angle is the ratio of two lengths namely arc length to the radius making it a dimensionless quantity. Angle is not a basic quantity because it is defined by another basic quantity i.e. length.


6. Perfect reproducibility means the instrument has:

  1. No drift
  2. High accuracy
  3. Maximum drift
  4. Minimum accuracy

Answer.1. No drift


The reproducibility of an instrument is how close the measurements of a single test sample are when the same measurement procedures are used but when the operator, the instrument and/or the laboratory are changed.

Perfect reproducibility means that the instrument has no drift. No drift means that with a given input the measured values do not vary with time.


7. Which standard is fixed and used for industrial laboratories?

  1. International standard
  2. Primary standard
  3. Secondary standard
  4. Working standard

Answer.3. Secondary standard


Secondary Standards are the basic reference standards used by industrial laboratories and are maintained by the particular industry to which they belong. They are periodically sent to a national laboratory for calibration and verification against primary standards.


8. What is the smallest change in the input signal that can be detected by an instrument called?

  1. Accuracy
  2. Precision
  3. Resolution
  4. Sensitivity

Answer.3. Resolution


The smallest change in output to the change in input is known as resolution. Resolution is the smallest measurable input change. Resolution is the number of significant digits (decimal places) to which a value is being reliably measured.


9. Which of the following error is caused by poor calibration of the instrument?

  1. Random error
  2. Gross error
  3. Systematic error
  4. Precision error

Answer.3. Systematic error


Systematic errors in experimental observations usually come from the measuring instruments. They may occur because of poor calibration of the instrument or its data handling system, or because the instrument is wrongly used by the experimenter.


10. A wattmeter reads 25.34 W. The absolute error in measurement is – 0.11 W. What is the true value of power:

  1. 25.23 W
  2. 25.45 W
  3. −25.23 W
  4. −25.45 W

Answer.2. 25.45 W


Given that,

Measured value = 25.34 W

Absolute error = – 0.11 W

Absolute error = Measured value – true value

⇒ -0.11 = 25.34 – true value

⇒ 25.34 + 0.11 = 25.45 W

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