| English | Physical quantity |
|---|---|
| Bahasa Melayu | Kuantiti fizik |
| 中文 | 物理量 |
Definition
A quantity that can be measured, consisting of a numerical value and a unit.
In exam terms
A physical quantity is any property that can be measured, and it always has two parts: a numerical value (magnitude) and a unit. A value written without a unit is meaningless in physics.
For example, the length of a wire may be written as l = 25 cm, where 25 is the value and cm is the unit. Physical quantities are grouped into base quantities (length, mass, time, current, temperature) and derived quantities (speed, density).
They may also be scalar or vector. Note that a symbol stands for the quantity (m for mass) while the unit is separate (kg).
Do not confuse it with the unit
Do not confuse a physical quantity with its unit. The quantity is the property measured, such as length; the unit is the agreed standard used to state it, such as the metre.
So current is a quantity, while the ampere is its unit.
In Paper 2, a question that says state the physical quantity measured by a stopwatch wants the answer time, not the unit second. Watch the command word: state asks for a short answer, while define asks you to explain that a quantity has a numerical value and a unit.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)