| English | Boyle's law |
|---|---|
| Bahasa Melayu | Hukum Boyle |
| 中文 | 玻意耳定律 |
Definition
For a fixed mass of gas at constant temperature, the pressure is inversely proportional to its volume (pressure × volume = constant).
In exam terms
Boyle's law states that for a fixed mass of gas at constant temperature, the pressure is inversely proportional to its volume. In symbols, pV = constant, or p₁V₁ = p₂V₂, where p is pressure in pascals (Pa) and V is volume in m³.
Microscopically, reducing the volume packs the gas particles closer, so they hit the walls more often each second, raising the pressure. Worked line: p₁V₁ = p₂V₂ → (100 kPa)(2.0 m³) = p₂(1.0 m³), so p₂ = 200 kPa.
Example of correct use: by Boyle's law, halving the volume of a trapped gas at constant temperature doubles its pressure.
Do not confuse it with…
Do not confuse Boyle's law with the pressure law. Boyle's law keeps the temperature constant and relates pressure to volume (an inverse relationship), while the pressure law keeps the volume constant and relates pressure to absolute temperature (a direct relationship).
Boyle's law does not use the Kelvin scale because temperature is fixed.
In Paper 2 this is usually asked as state Boyle's law, a calculation with p₁V₁ = p₂V₂, or a graph question. A graph of p against V is a curve, but a graph of p against 1/V is a straight line through the origin, which is the usual proof asked for.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)