Joule is a derived unit as, J = Nm, and N = kg m/s². So, joule depends upon many such physical units and hence, it is a derived unit.
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- Derived units: Units which are dependent on other physical units are known as derived units. Ex: acceleration (a), velocity (v).
- Fundamental units: Units which do not depend upon other units. Ex: cd (candela), kg (kilograms), etc.