UNIT AND DIMENSIONS
This course introduces students to the fundamental principles of physics, focusing on physical quantities, units of measurement, and the concept of dimensions. It provides a strong foundation for understanding the quantitative aspects of physical laws and their practical applications.
3. SYSTEMS OF UNITS:
1.3 SYSTEMS OF UNITS: CGS, FPS, MKS, SI
For measurement of physical quantities, the following systems are commonly used:-
(i) F.P.S system: In this system, the unit of length is foot, the unit of mass is pound and the unit of time is second.
(ii) C.G.S system: In this system, the unit of length is centimeter, the unit of mass is gram and the unit of time is second.
(iii) M.K.S: In this system, the unit of length is metre, unit of mass is kg and the unit of time is second.
(iv) S.I System: This system is an improved and extended version of M.K.S system of units. It is called international system of unit.
With the development of science & technology, the three fundamental quantities like mass, length & time were not sufficient as many other quantities like electric current, heat etc. were introduced.
Therefore, more fundamental units in addition to the units of mass, length and time are required.
Thus, MKS system was modified with addition of four other fundamental quantities and two supplementary quantities.
Advantage of S.I. system:
(i) It is coherent system of unit i.e. the derived units of a physical quantities are easily obtained by multiplication or division of fundamental units.
(ii) It is a rational system of units i.e. it uses only one unit for one physical quantity. e.g. It uses Joule (J) as unit for all types of energies (heat, light, mechanical).
(iii) It is a metric system of units i.e. it’s multiples & submultiples can be expressed in power of 10.