what do u understand by SI units
The International System of Units (abbreviated SI from systeme internationale, the French version of the name) is a scientific method of expressing the magnitudes or quantities of important natural phenomena.There are seven base units in the system, from which other units are derived.I base units: The meter (abbreviation, m) is the SI unit of displacement or length. One meter is the distance traveled by a ray of electromagnetic (EM) energy through a vacuum in 1/299,792,458 (3.33564095 x 10 -9) second.