The Role of Physical Quantities and Units
When we study physics, we mostly talking about objects. In our mind click some basic questions. For example: how big is an object? How much mass does it have? To solve all these examples of questions, they make measurements with several instruments (e.g., balance, stopwatch, meter stick, etc.).
The measurements of physical quantities are manifested in terms of units, which are standardized values. For example, the length of a cable, which is a physical quantity, can be displayed in meters or kilometers.
All physical quantities in the SI system of units are communicated in words of keys of seven fundamental physical units which is given below:
| SI Base Unit | ||
|---|---|---|
| Fundamental Quantity | Unit Name | Symbol Of Unit |
| length | meter | m |
| electric current | ampere | a |
| temperature | kelvin | k |
| mass | kilogram | kg |
| time | second | s |
| amount of substance | mole | mol |
| luminous intensity | candela | cd |