Question

The S.I. unit of mass is __________.
a.) Kilogram
b.) Gram
c.) Decigram
d.) Milligram

Answer 1

Hint: The S.I. unit of mass is equal to mass of 1000 $c{m^3}$ of water. It is the quantity which is highest of all options available.

Complete answer:
First we will see what mass is.
Mass can be defined as the measure of physical 3D structure and quantity of a substance.
Mass of a substance is mostly measured in kilograms and grams. The kilogram is S.I. unit of mass. It is also written as- ‘kg’.
The gram is C.G.S. unit of mass.
Thus, option a.) is the correct answer.

Additional information:
The S.I. units are the standard units given by the International System of units. They have taken seven basic quantities and fixed their units. All other units are derived from them.
The seven base quantities and their S.I. units are
Time – Second (s)
Length – Metre (m)
Mass – Kilogram (Kg)
Electric current – Ampere (A)
Temperature – Kelvin (K)
Amount of substance – Mole (mol)
Luminous intensity - Candela (cd)
The units derived from these fundamental units are called Derived units. Example – Velocity is the derived unit from length and time.
There are some units like litre and electron volt; these are not part of S.I. unit but are accepted to use with it.

Note: Mass is different from weight. Many of us get confused between mass and weight. Mass is a scalar quantity and contains the quantity of matter. While the weight is the product of force that is applied on the matter by Earth and quantity of matter. Weight is a vector quantity.