A barometer is carried from a valley up to a plateau. Its reading is lower on the plateau.
Which statement explains the lower reading on the plateau?
Less air lies above the plateau, so the air there is less dense and fewer particles hit each square metre each second.
The air at the plateau is denser, so its particles collide with each other more and hit the barometer less often.
Less air lies above the plateau, so the air there is more compressed and fewer particles hit each square metre each second.
Gravity is too weak at the plateau to pull the air down, so fewer particles hit each square metre each second.
132 exam-style questions on Edexcel GCSE Physics 15.2 Pressure in fluids, covering 15.2.1 Atmospheric pressure and height, 15.2.2 Pressure in fluids, 15.2.3 Pressure, force and area, 15.2.4 Pressure and depth, 15.2.5 Pressure in liquids: depth and density, 15.2.6 Upthrust, and 15.2.7 Floating and sinking. Each one has a worked solution and a mark scheme showing where the marks go.