Brownian motion is the random movement of suspended particles in a fluid.
Which of the following correctly describes the cause of Brownian motion and the states of matter in which it can be observed?
It is caused by the bombardment of suspended particles by fast-moving fluid molecules, and it is observed in liquids and gases only.
It is caused by the bombardment of suspended particles by fast-moving fluid molecules, and it is observed in solids, liquids, and gases.
It is caused by convection currents carrying the suspended particles, and it is observed in liquids and gases only.
It is caused by electrostatic attraction between the suspended particles, and it is observed in gases only.
151 exam-style questions on CIE IGCSE Physics 2.1.2a Particle structure and motion in solids, liquids and gases. Each one has a worked solution and a mark scheme showing where the marks go.