Question

Name the basic and supplementary unit of SI

Answer 1

Basic SI Units

Physical quantity quantity
symbol Basic SI
Unit Name Unit Symbol
length l, b, d, h, r, s, etc. metre m
mass m kilogram kg
time t second s
electric current I ampere A
thermodynamic temperature T kelvin K
amount of substance n mole mol
luminous intensity Iv candela cd.




Supplementary Dimensionless SI Units

Quantity Quantity
symbol SI Unit Name Unit Symbol Exp. in SI base units
plane angle α, β, γ, θ, Φ radian rad m m-1
solid angle ω, Ω steradian sr m2 m-2

Answer 2

Basic and supplementary units of SI systems:-

Kelvin:- It is the unit of temperature.

Ampere :-this is the unit of current.

Candela :- It was adopted as the units of luminous intensity.

Mole :- this is the unit of amount of any substance.

Radian :- this is the unit of plane angle

Steradian :- It was adopted as the unit of plane angle.

Parallactic second (parsec) :- It was adopted as the largest practical unit of distance.

• 1 parsec = 3.08 × 10^16 m = 4.2 light year

Light year :- It is also known as practical unit of distance which is used in astronomy to measure the distance of nearer stars.

Astronomical unit :- this unit is defined as the average distance between sun and earth,

I. e., radius of earth's orbit.

1 A. U. = 1.496 × 10^11 m

Microns:- it is a unit of distance defined as micrometre.

1 microns = 10^(-6) m

Angstrom :- It is also practical unit of length which used in atomic physics.

1 angstrom = 10^(-10) m

Fermi :- this is the smallest practical unit of distance which is used in nuclear physics.

1 Fermi = 10^(-15) m