IGCSE Physics

 

Physical Quantities

A physical quantity is a property of an object that can be measured with a measuring instrument.

A physical quantity is usually expressed as “a magnitude (numerical value) and a physical unit or more”

Example:-

Normal body temperature of a healthy human being is 37 ⁰C

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37      is the number (value) +

⁰C       is the unit

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Systems of units

We had several systems for units which might still be used in some countries.

SI units “International system of units”

 

Basic SI units (we will start only with three of them)

Quantity	Name of SI Unit	Symbol	Device used to measure
Length	meter	m	Meter rule
Mass	kilogram	kg	Balance
Time	second	s	Stopwatch

the first three is enough for starting our course, the rest will be studied later