Deck 1: Measurements & SI Units

Physical Quantity

A measurable quantity with a magnitude (number) and a unit.

Importance of Units

A measurement without a unit has no meaning.

SI Base Quantities

The 7 fundamental physical quantities from which all other quantities are derived.

Length (Base Quantity)

Quantity symbol: l; SI unit: metre (m).

Mass (Base Quantity)

Quantity symbol: m; SI unit: kilogram (kg).

Time (Base Quantity)

Quantity symbol: t; SI unit: second (s).

Electric Current (Base Quantity)

Quantity symbol: I; SI unit: ampere (A).

Temperature (Base Quantity)

Quantity symbol: θ; SI unit: kelvin (K).

Amount of Substance (Base Quantity)

Quantity symbol: n; SI unit: mole (mol).

Luminous Intensity (Base Quantity)

Quantity symbol: L; SI unit: candela (cd).

Derived Quantity

A quantity calculated from one or more SI base quantities.

Area

Formula: length × width; SI unit: m².

Volume

Formula: length × width × height; SI unit: m³.

Speed

Formula: distance ÷ time; SI unit: m/s.

Nano

Symbol: n; 10⁻⁹.

Micro

Symbol: μ; 10⁻⁶.

Milli

Symbol: m; 10⁻³.

Centi

Symbol: c; 10⁻².

Deci

Symbol: d; 10⁻¹.

Kilo

Symbol: k; 10³.

Mega

Symbol: M; 10⁶.

Giga

Symbol: G; 10⁹.

1 cm

10 mm.

1 m

100 cm.

1 km

1000 m.

1 kg

1000 g.

1 hour

3600 s.