physic is the part of fundamental science that deals with the study of natural phenomena.firstly physic deals with the study of measurement and its units that most important in our basic life for basic use.In physic we are to deal with large number of physical quantities like length, mass, time, velocity, force, pressure e.t.c.These quantities can give clear understanding only if we can measure them any kind of basic units.Due this reason, physic is sometime called as the science of measurement.
THEREFORE, THE PROCESS OF COMPARING AN UNKNOWN PHYSICAL QUANTITY WITH A KNOWN FIXED QUANTITY IS CALLED MEASUREMENT.
The quantity used as a standard of measurement is called as the unit.