Fundamental Quantities And Their Units - SS1 Physics Lesson Note

Fundamental quantities are the basic physical quantities that are not defined in terms of other quantities. They are those basic physical quantities which do not depend on any other physical quantities for their measurement. Thus, they form the foundation for the measurement of other physical quantities. In the International System of Units (SI), there are seven fundamental quantities:

1. Length: The fundamental quantity for measuring distances. Its unit is the meter (m).

2. Mass: The fundamental quantity for measuring the amount of matter in an object. Its unit is the kilogram (kg).

3. Time: The fundamental quantity for measuring the duration of events. Its unit is the second (s).

4. Electric Current: The fundamental quantity for measuring the flow of electric charge. Its unit is the ampere (A).

5. Temperature: The fundamental quantity for measuring the degree of hotness or coldness. Its unit is the Kelvin (K).

6. Amount of Substance: The fundamental quantity for measuring the number of entities (such as atoms or molecules) in a substance. Its unit is the mole (mol).

7. Luminous Intensity: The fundamental quantity for measuring the intensity of light emitted by a source. Its unit is the candela (cd).

These fundamental quantities are considered the building blocks of measurement in physics, and all other physical quantities can be derived from them. For example, velocity is derived from length and time, and density is derived from mass and volume.