Diploma Measurement and Metrology Study Material

## Diploma Measurement and Metrology Study Material – Unit 1 Diploma N Scheme

### Diploma Measurement and Metrology Study Material

Dear friends

We have added Diploma Measurement and Metrology Study Material for the unit 1 Basic Concepts of Measurements

Subject:  Measurements and Metrology                               Scheme: N

Unit 1: Basic Concepts of Measurements

Three Marks

1. What is Metrology?

Metrology is the science of measurement. Engineering Metrology is related to the measurement of lengths, angles and other quantities that are expressed in linear or angular terms

1. Mention any three objectives of metrology.

The objectives of Metrology are

1. To provide the required accuracy at minimum cost
2. To minimize the cost of inspection
3. To ensure the capability of measuring instruments
4. To standardize the various measuring instruments
5. To maintain the accuracy of the instrument by calibrating them periodically
1. What are the systems of measurement?
• P.S Systems
• Metric Systems
• S. I. System

4.List the methods of Measurement.

1. Linear measurement
2. Angular measurement
3. Direct method
4. Indirect method
5. Comparative method
6. Coincidence method
7. Contact method
1. What are the standards of measurement?

There are two standards for measurement

1. Line standard
2. End standard
1. What is end standard?

When the distance (length) is measured between two surfaces or faces it is called as End standard

1. What is line standard?

When the distance (length) is measured between two lines it is called line standard

1. What is the element of measurement?

There are five Basic  elements of measurement it is termed as SWIPE

1. Standard (S)
2. Workpiece (W)
3. Instrument (I)
4. Person (P)
5. Environment (E)
1. What is legal metrology?

Legal metrology is concerned with the regulations and legal requirements for the measuring instruments and methods of measurements

1. What is precision?

Precision is the closeness of arrangement between independent test results obtained under specified conditions. Precision indicates the degree of responsibility in the measuring process

1. What is accuracy?

Accuracy is the closeness of agreement between the measured value and its true value. The difference between the true value and the measured value is known as Error of Measurement

1. What is sensitivity?

Sensitivity is defined as the ability of an instrument to detect small differences in the quantity being measured.

1. What is calibration?

The process of periodically checking the measuring instruments and keeping the standards of the measuring instruments with high accuracy is called as calibration

1. What is magnification?
• Magnification is the process of measuring small difference in dimensions
• In magnification process, the movement of the measuring tip in contact with the workpiece must be magnified.
• Magnification may be achieved by mechanical, electrical, optical, pneumatic principle
1. What is interchangeability?

Interchangeability is used in Mass production, In mass production, any part should assemble satisfactorily with any other mating part. Interchangeability is possible when common standards are established

1. What is reliability?

Reliability is the ability of an instrument to perform function over a period of time

1. Define Error.

Error in measurement is defined as the difference between measured value and true value

Error = Measured Value – True Value

1. What are the sources of error?
1. Calibration of the instrument
2. Workpiece
3. Operator’s skill
4. Measuring arrangement
5. Environmental condition
2. What are the classifications of error?

Errors in measurement is classified based on nature sources mentioned below.They are

1. Gross Error
2. Systematic error
3. Random or Environmental Error