CBSE
Class 10
Class 12
To find the unit of a physical quantity in a given system of units: Writing the definition or formula for the physical quantity we find its dimensions. Now in the dimensional formula replacing M, L and T by the fundamental units of the required system we get the unit of physical quantity. However, sometimes to this unit we further assign a specific name, e.g., Work = Force x Displacement
so [W]= [MLT-2] x [L] = [ML2T-2]
So its units in C.G.S system will be g cm2/s2 which is called erg while in the M.K.S system will be kg m2/s2 which is called joule.