A flexible packet contains a fixed mass of air. The packet is moved to a place where the atmospheric pressure is lower. It expands slowly, so the temperature of the air remains constant.
Explain, in terms of particles, why the pressure of the air inside the packet decreases as the packet expands.
108 exam-style questions on Edexcel GCSE Physics 14.3 Gas pressure and temperature, covering 14.3.1 Gas pressure and particle motion, 14.3.2 Temperature and pressure at constant volume, 14.3.3 Absolute zero and the kelvin scale, 14.3.4 Compressing and expanding gases, 14.3.5 Volume and pressure at constant temperature, and 14.3.6 Doing work on a gas. Each one has a worked solution and a mark scheme showing where the marks go.