The following systems of fundamental units have been in use:
1.C.G.S System :In this system,the unit of length is centimetre,the unit of mass is gram and the unit of time is second.The centimetre is one-hundredth part of a metre.The gram is one thousandth part of kilogram.
2. 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 the second.The foot is one-third of the distance between two lines on a platinum-irridium alloy bar at a temperature of 62 F kept at the standard office of the board of trade,london.The pound is the mass of platinum-irridium cylinder kept at the standard office of b.o.t,London.The second is defined as 1/86400 th part of mean solar day.
3.M.K.S System: The unit of length in this system is meter,the unit of mass is kilogram and the unit of time is second.This system is a metric system and was first time introduced in 1901 by 'a'. giorgi,this system with same modifications formed the basis of s.i.units,which is now used in all the scientific work.
4.S.I.(system International Units):French name of this system is system international de units (english meaning:international system of units) abbreviated as s.i units.This system in an improved and extended version of m.k.s system of units.
With the development of science and technology the three fundamental quantities like mass,length and time were not sufficient as many other physical phenomenon like light,heat,electricity etc.came up.
These physical phenomenon required more fundamental units in addition to the existing units of mass,length and time.Therefore,m.k.s. system was modified with the addition of four other fundamental quantities.This gave rise to international system of units abbreviated as s.i for system International.
1.C.G.S System :In this system,the unit of length is centimetre,the unit of mass is gram and the unit of time is second.The centimetre is one-hundredth part of a metre.The gram is one thousandth part of kilogram.
2. 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 the second.The foot is one-third of the distance between two lines on a platinum-irridium alloy bar at a temperature of 62 F kept at the standard office of the board of trade,london.The pound is the mass of platinum-irridium cylinder kept at the standard office of b.o.t,London.The second is defined as 1/86400 th part of mean solar day.
3.M.K.S System: The unit of length in this system is meter,the unit of mass is kilogram and the unit of time is second.This system is a metric system and was first time introduced in 1901 by 'a'. giorgi,this system with same modifications formed the basis of s.i.units,which is now used in all the scientific work.
4.S.I.(system International Units):French name of this system is system international de units (english meaning:international system of units) abbreviated as s.i units.This system in an improved and extended version of m.k.s system of units.
With the development of science and technology the three fundamental quantities like mass,length and time were not sufficient as many other physical phenomenon like light,heat,electricity etc.came up.
These physical phenomenon required more fundamental units in addition to the existing units of mass,length and time.Therefore,m.k.s. system was modified with the addition of four other fundamental quantities.This gave rise to international system of units abbreviated as s.i for system International.