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.
321 exam-style questions on CIE IGCSE Physics 2.1 Kinetic particle model of matter, covering 2.1.1 States of matter and changes of state, 2.1.2a Particle structure and motion in solids, liquids and gases, 2.1.2b Gas pressure and particle collisions, 2.1.2c Brownian motion, 2.1.3a The absolute scale of temperature, and 2.1.3b Pressure, volume and temperature of a gas. Each one has a worked solution and a mark scheme showing where the marks go.