1. What is meant by measurement?
Measurement means an act or the result of comparison between the quantity and a
2. Mention the basic requirements of measurement.
The basic requirements of measurement are
i. The standard used for comparison purpose must be accurately defined and should be commonly accepted.
ii. The apparatus used and the method adopted must be provable.
3. State the two methods for measurement.
The two methods of measurement are
i. Direct method and
ii. Indirect method.
4. State the function of measurement system.
The measurement system consists of a transducing element which converts the quantity to be measured in an analogous form the analogous signal is then processed by some intermediate means and is then fed to the end device which presents the results of the measurement.
5. List the three types of instruments.
The three types of instruments are:
i. Mechanical Instruments
ii. Electrical Instruments and
iii. Electronic Instruments.
6. Classify the instrument based on their functions.
Instruments are classified into three types based on their functions. They are
i. Indicating instruments
ii. Integrating instruments
iii. Recording instruments
7. Give any three applications of measurement systems.
The applications of measurement systems are
i. Monitoring of processes and operations.
ii. Control of processes and operations.
iii. Experimental engineering analysis.
8. Why calibration of instrument is important?
The calibration of all instruments is important since it affords the opportunity to check the instrument against a known standard and subsequently to errors in accuracy.
9. List the calibration procedure.
Calibration procedure involves a comparison of the particular instrument with either.
A primary standard
A secondary standard with a higher accuracy than the instrument to be calibrated or An instrument of known accuracy.
10. Define: Calibration
Calibration is defined as the process by which comparing the instrument with a standard to correct the accuracy.
11. Mention the functions performed by the measurement system.
The functions performed by the measurement system are
i. Indicating function
ii. Recording function
iii. Controlling function
12. List the functional elements of the measurement systems.
The three main functional elements of the measurement systems are:
i. Primary sensing element
ii. Variable conversion element
iii. Data presentation element
13. Write the characteristics of the measurement system.
Characteristics of measurement system is divided into two categories:
i. Static characteristics
ii. Dynamic characteristics
14. Write the main static characteristics?
The main static characteristics are:
v. Static error
vi. Dead zone
15. Define static error
Static error is defined as the difference between the true value and the measured value of the quantity. Static error
= At – Am
Am =measured value of quantity
At =true value of quantity.
16. Define resolution
Resolution is defined as the smallest increment of quantity being measured which can be detected with certainty being measured which can be detected with certainty by an instrument.
17. Define threshold
Threshold is defined as the minimum value of the input at which the output starts
changing/increasing from zero.
18. Define linearity
The linearity is defined as the ability to reproduce the input characteristics symmetrically and linearly.
19. Define reproducibility
Reproducibility is defined as the degree of closeness with which a given value may be repeatedly measured. It is specified in terms of scale readings over a given period of time.
20. Define drift
Drift is defined as slow variation of reading from a fixed value.
21. Define speed response
Speed response is defined as the rapidity with which a measurement system responds to changes in measured quantity. It is one of the dynamic characteristics of a measurement system.
22. Define fidelity
Fidelity is defined as the degree to which a measurement system indicates changes in the measured quantity without any dynamic error.
23. Define dynamic error
Dynamic error is defined as the difference between the true value of the quantity changing with time and the value indicated by the measurement system if no static error is assumed. It is also called measurement error. It is one the dynamic characteristics.
24.Define retardation delay
Retardation delay is defined as the retardation delay in the response of a measurement system to changes in the measured quantity.
25. Define time delay
Time delay is defined as the response of the measurement system begins after a dead zone after the application of the input.