Which statement correctly describes the Brownian motion of pollen grains suspended in water?
It allows the observer to directly see the motion of individual water molecules.
It is caused by the collisions between the pollen grains themselves.
It is caused by the random collisions of water molecules with the pollen grains.
It only occurs because pollen grains are living organisms that swim through the fluid.
48 exam-style questions on AQA A Level Physics Thermal physics (A-level only), covering Thermal energy transfer (A-level only), Ideal gases (A-level only), and Molecular kinetic theory model (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.