CBSE Class 11-science Answered

The SI system is a system of units that is used to qualify or express the nature of the  measured quantity.It has the following advantages

1. Its a coherent system:All units can be derived from the fundamental units through multiplication and division.
                                      Eg. SI unit of speed = metre/second
2. Its a rational system: It assigns only one unit for each physical quantity.For eg. Joule is a unit for all type of quantities.This is not the case in other units eg in m.k.s system Joule is a unit for mechanical energy.,calorie for heat etc

3. Its a metric system:Multiples and sub multiples of units are expressed as powers of 10.

All these advantages make the SI system of Units practical and comprehensible.