Question

What is a unit symbol for a nanometer?

Answer 1

Hint: Generally symbols are used to represent every unit, so that we can get a clear idea to write the unit in an easy way and also learn them easily. Here in this question we have to write the symbol to nanometre like Unit of Temperature is Kelvin and symbol used to represent it is K Similarly unit id length is metre and symbol used is m and also symbol for Ampere is A.

Complete step-by-step solution:
Units are used to complete any physical quantity as without unit no measurement is completed. Every Physics quantity is expressed as a combination of numbers along with its unit.
Let us assume Physical Quantity is represented as$$Q$$.
$$Q=n\times u$$
Where $$n$$represents the number while $$u$$ represents the unit.
Unit can be classified into three categories like – Fundamental unit, Derived Unit and Supplementary unit.
There are seven Fundamental quantities and for each fundamental quantity a unit is associated and to express each unit a symbol is required which provides an easy way to write the unit. Some examples of fundamental units are:-
1. Unit of length is metre and symbol is $$(m)$$
2. Unit of Mass is Kilogram and symbol is $$(Kg)$$
3. Unit of Time is second and the symbol is$$(s)$$.
In this question we have to write the symbol of the nanometer. As a nanometer is used to measure the small length, it can also be expressed in a symbol called$$(nm)$$. These symbols are designed to write a unit in an easy way. As a nanometer starts from n then why its symbol is not marked as n because n is already given to the unit of force. Unit of force is Newton and the symbol is$$(N)$$. When the first letter of any unit is already used for some other unit then the symbol of that unit is formed by taking the first two letters of that unit.
Nanometer can also expressed in metre by using the simple conversion as
$$1nm={10}^{-9}m$$
So finally we can conclude that the unit symbol used to represent a nanometer is$$(nm)$$.

Note: Other than fundamental and derived quantities, two new quantities are developed called plane angle and solid angle that comes under supplementary quantities. Plane angle is found in a circle and its unit is marked as radian while Solid angle is found in sphere and its unit is marked as Steradian. Both are dimensionless quantities.