A weather balloon is partly filled with helium at ground level.
At ground level, the volume of the balloon is 4.0 m3, the pressure of the helium is 100 kPa and the temperature of the helium is 15 ∘C15\ ^{\circ}\text{C}15 ∘C.
As the balloon rises, the atmospheric pressure decreases. The rubber of the balloon stretches easily, so the pressure of the helium is always equal to the atmospheric pressure.
Give the temperature of the helium at ground level in kelvin.
At a height of 10 km, the atmospheric pressure is 26 kPa.
Calculate the volume of the balloon at this height. Assume that the temperature of the helium does not change.
Use the equation
P1×V1=P2×V2P_1 \times V_1 = P_2 \times V_2P1×V1=P2×V2
At a height of 10 km, the temperature of the helium is actually −50 ∘C-50\ ^{\circ}\text{C}−50 ∘C.
Explain how the actual volume of the balloon at this height compares with your answer to (b).
Calculate the decrease in temperature of the helium, in kelvin, between ground level and a height of 10 km.
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.