O-LevelPhysicsThermal Physics5054/21 · Oct/Nov 2014 · Q35 Marks
Before a small, inflatable boat is used, air is pumped into its rubber chamber. Fig. 3.1 shows a man using an air pump to inflate the boat. [Figure 3.1] Before the man starts to use the pump, the air in the vertical cylinder of the pump is at atmospheric pressure.
- (a)Explain, in terms of molecules, how the air inside the cylinder exerts a pressure.[3]
- (b)When the boat is fully inflated, a valve is closed trapping the air in the rubber chamber. The air pump is disconnected. The man sits on the side of the boat. The volume of the rubber chamber decreases and the pressure of the air in the rubber chamber increases. The temperature of the air stays constant. Explain, in terms of molecules, why the pressure increases.[2]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2014). The mark or mark type is shown in brackets.
- [3] (a) (atoms/molecules/particles) move (about)/collide/hit
- (atoms/molecules/particles) collide/hit the walls/surface (of the cylinder)
- force on walls (causes pressure)
- [2] (b) atoms/molecules/particles closer/more compact/more molecules per unit volume/less space to move
- more collisions with the wall/surface (of chamber) not if speed/KE changes
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →