Units are defined for physical quantities and units of measurements are nothing but definite magnitude of these physical quantities. These units of measurement are derived and adopted after some conventions or laws and now we are using these units as a standard for measurement of the physical quantity.
There are various systems for defining units of measurement:
1. Traditional System: It was used in ancient time.
2. Metric Systems: It is the system which is being used universally. Many metric systems have been evolved after the adoption of original metric system in 1791. But the standard metric system which is globally used is the International Systems Of Units (SI), it is also known as the modern form of metric system.
3. Natural Systems: This system consists of unit values which occur naturally in science. They include atomic units (au), solar mass, the megatons etc.
Here are seven units of measurement which are evolved or derived as a basic set from which all other SI units are derived and their corresponding physical quantities:
1. Length meter (which represents a definite predefined length , i.e., if we say 5 Metre or 5m, we mean 5 times the predefined length called “meter”)
2. Time seconds
3. Electric Current Ampere
4. Mass Kilogram
5. Temperature Kelvin
6. Luminous Intensity candela (cd)
7. Amount of substance mole (mol)
We can derive any other physical quantity by simply multiplying units of measurement.
Units of measurement have been playing a very significant role in various tasks since 1791: like fashioning clothing, construction of dwellings of definite size and shape, physics, medicine, metrology etc.
Here is one example of how the derivation of other units takes place from the above seven units of measurement:
Area – the SI unit is meter square (m2)
A=Length * breadth (area of rectangle)
A= m * m = m2 (meter square)
As SI unit of length and breadth is meter (m).
Like that we derive many more units.
In the next session we are going to discuss Error and magnitude.
There are various systems for defining units of measurement:
1. Traditional System: It was used in ancient time.
2. Metric Systems: It is the system which is being used universally. Many metric systems have been evolved after the adoption of original metric system in 1791. But the standard metric system which is globally used is the International Systems Of Units (SI), it is also known as the modern form of metric system.
3. Natural Systems: This system consists of unit values which occur naturally in science. They include atomic units (au), solar mass, the megatons etc.
Here are seven units of measurement which are evolved or derived as a basic set from which all other SI units are derived and their corresponding physical quantities:
1. Length meter (which represents a definite predefined length , i.e., if we say 5 Metre or 5m, we mean 5 times the predefined length called “meter”)
2. Time seconds
3. Electric Current Ampere
4. Mass Kilogram
5. Temperature Kelvin
6. Luminous Intensity candela (cd)
7. Amount of substance mole (mol)
We can derive any other physical quantity by simply multiplying units of measurement.
Units of measurement have been playing a very significant role in various tasks since 1791: like fashioning clothing, construction of dwellings of definite size and shape, physics, medicine, metrology etc.
Here is one example of how the derivation of other units takes place from the above seven units of measurement:
Area – the SI unit is meter square (m2)
A=Length * breadth (area of rectangle)
A= m * m = m2 (meter square)
As SI unit of length and breadth is meter (m).
Like that we derive many more units.
In the next session we are going to discuss Error and magnitude.
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