Explain fundamental units.
Answers
Fundamental units are those set of unrelated units of measurement which are defined arbitrarily and from which other units are formed or derived. It is the unit of measurement for a measurable physical property. They are not dependent on any other units and are used for the measurement of base quantities in physics.
The International System of Units (SI) consists of 7 fundamental units and all the units derived from them.
The seven basic units are:
Meter [m] = length, defined by the speed of light.
Kilogram [kg] = weight, defined by the Kilogram Prototype in Paris, will be redefined with fundamental constants of nature sooner or later.
Second [s] = time, defined by the physical properties of a certain kind of Cesium atom (Cs-133).
Ampere [A] = electric current, defined by the force between two hypothetical electric conductors.
Kelvin [K] = temperature, defined by the thermodynamic properties of water (the triple point specifically).
Mole [mol] = amount of substance, defined by the number of atoms contained by 12 grams of a certain type of Carbon (C-12).
Candela [cd] = luminous intensity, defined by a certain type of radiation with a specific radiant density.