Question

What is basic quantity?

Answer 1

A base quantity is a physical quantity in a subset of a given system of quantities that is chosen by convention, where no quantity in the set can be expressed in terms of the others. The ISQ defines seven base quantities. The symbols for them, as for other quantities, are written in italics.

Answer 2

base quantity (or basic quantity) is chosen and arbitrarily defined, rather than being derived from a combination of other physical quantities.

The 7 base quantities are:

Physical quantity Base SI unit

Mass (m) Kilogram (Kg)

Length (

l

) Metre (m)

Time (t) Second (s)

Current (

I

) Ampere (A)

Temperature (T) Kelvin (K)

Amount of sub. (n) Molar (mol)

Luminous Intensity (L) Candela (cd)

SI units are used as standardised units in all measurements in the world. SI is the short form for “International System of Units”.