Encyclopedia of Electrical Engineering

A physical quantity is a quantity which can be measured. For example length, weight, volume etc are physical quantity. By using these physical quantities we can find some basic attributes of an object.
#### Fundamental Quantities

Those quantities which do not depend on other quantities are the fundamental quantities. There are seven fundamental quantities. These are *Length*, *Mass*, *Time*, *Electric Current*, *Temperature*, *Luminous Intensity* and *Amount of Matter*.
#### Derived Quantities

Those quantities which are dependent on fundamental quantities are termed as derived quantities. Examples of derived quantities are Area, Volume, Speed, Force, Work etc.
**Fig.no.1: ** Fundamental Quantities with units and symbols.
**Fig.no.2: ** Derived Quantities with units and symbols.
#### Scalar Quantities

A physical quantity which can be expressed only by magnitude (By a numerical value) is known as scalar quantity. Mass, Time, Temperature, Speed, work are scalar quantities.
#### Vector Quantities

Those quantities which need both magnitude and direction to express the quantity completely and also follow the laws of vector algebra are the Vectors.
**Figure no.3:** Scalar Quantities
**Fig.no.4: **Difference between scalar and vector

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