- Physical quantity
- A quantity that can be measured, consisting of a numerical value and a unit.
- Base quantity
- A physical quantity that cannot be defined in terms of other physical quantities; the five in physics are length, mass, time, electric current and temperature.
- Derived quantity
- A physical quantity obtained by combining base quantities through multiplication or division, such as speed or density.
- Scalar quantity
- A physical quantity that has magnitude only, with no direction, such as distance, speed and mass.
- Vector quantity
- A physical quantity that has both magnitude and direction, such as displacement, velocity and force.
- SI unit
- The internationally agreed system of units for physical quantities, based on the seven SI base units such as the metre, kilogram and second.
- Prefix
- A word or symbol placed before a unit to indicate a multiple or fraction of it, such as kilo- (10³) or milli- (10⁻³).
- Significant figures
- The digits in a measurement that carry meaningful information about its precision.
- Measurement error
- The difference between a measured value and the true value of a quantity.
- Precision
- The ability of an instrument to give consistent, closely grouped readings when a measurement is repeated.
- Accuracy
- How close a measured value is to the true or accepted value of a quantity.
- Sensitivity
- The ability of an instrument to detect and respond to a small change in the quantity being measured.
What "Measurement" terms cover
This group collects the 12 SPM Physics terms in Measurement. Getting these definitions exactly right is some of the cheapest marks in Paper 2, a "define" or "state" question wants one precise sentence with the correct unit.
The key terms to get right
- Physical quantity, A quantity that can be measured, consisting of a numerical value and a unit.
- Base quantity, A physical quantity that cannot be defined in terms of other physical quantities; the five in physics are length, mass, time, electric current and temperature.
- Derived quantity, A physical quantity obtained by combining base quantities through multiplication or division, such as speed or density.
- Scalar quantity, A physical quantity that has magnitude only, with no direction, such as distance, speed and mass.
- Vector quantity, A physical quantity that has both magnitude and direction, such as displacement, velocity and force.
- SI unit, The internationally agreed system of units for physical quantities, based on the seven SI base units such as the metre, kilogram and second.
- Prefix, A word or symbol placed before a unit to indicate a multiple or fraction of it, such as kilo- (10³) or milli- (10⁻³).
- Significant figures, The digits in a measurement that carry meaningful information about its precision.
- Measurement error, The difference between a measured value and the true value of a quantity.
- Precision, The ability of an instrument to give consistent, closely grouped readings when a measurement is repeated.
- Accuracy, How close a measured value is to the true or accepted value of a quantity.
- Sensitivity, The ability of an instrument to detect and respond to a small change in the quantity being measured.
How this vocabulary is examined
These terms appear as define/state items in Paper 1 and Paper 2, and inside explain and calculate questions where using the wrong word costs marks. Learn each term with its unit and one example of correct use.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)