Physics > Unit and Dimensions > 3.0 SI units
Unit and Dimensions
1.0 Introduction
2.0 Physical quantity
3.0 SI units
3.1 Definition of standard units
3.2 System of units
3.3 Rules for writing units
3.4 Characteristics of a standard unit
3.5 Advantages of SI
4.0 SI prefixes
5.0 Conversion of units
6.0 Important practical units
7.0 Dimensions
8.0 Dimensional formula
9.0 Dimensional equation
10.0 List of dimensional formula
11.0 Application of dimensional analysis
11.1 To check the dimensional consistency of equations
11.2 To deduce relation among the physical quantities
11.3 To convert one system of unit into another system of unit
12.0 Limitations of dimensional analysis
3.4 Characteristics of a standard unit
3.2 System of units
3.3 Rules for writing units
3.4 Characteristics of a standard unit
3.5 Advantages of SI
11.2 To deduce relation among the physical quantities
11.3 To convert one system of unit into another system of unit
A unit selected for measuring a physical quantity should fulfill the following requirements.
- It should be well defined.
- It should be easily accessible.
- It should be of suitable size.
- It should not change with time.
- It should be easily reproducible at all places.
- It should not change with the change in its physical conditions like temperature, pressure etc.