Question

What do we call the principal SI units that are used to derive all other SI units? Question 3 options:

Answer 1

Answer: Base units

The principal SI units that are used to derive all other SI units are called base units. The base units are the units of fundamental quantities e.g.  M L T that is Mass, Length, and Time. All other physical quantities can be written in the fundamental dimension forms. The physical quantities are not measured directly but are build up from the building blocks that are the fundamental quantities which have base units.