GCE A-Level Physics Syllabus

Chapter 8: Thermal Physics

Chapter Topics:

Thermal equilibrium
Temperature scales
Equation of state
Kinetic theory of gases
Kinetic energy of a molecule

Question Bank:

Learning Objectives:

(a) Show an understanding that regions of equal temperature are in thermal equilibrium.

(b) Explain how empirical evidence leads to the gas laws and to the idea of an absolute scale of temperature (i.e. the thermodynamic scale that is independent of the property of any particular substance and has an absolute zero).

(c) Convert temperatures measured in degrees Celsius to kelvin: T/K = T / °C + 273.15

(d) Recall and use the equation of state for an ideal gas expressed as pV = nRT, where n is the amount of gas in moles.

(e) State that one mole of any substance contains 6.02 × 10²³ particles and use the Avogadro number NA = 6.02 × 10²³ mol⁻¹.

(f) State the basic assumptions of the kinetic theory of gases.

(g) Explain how molecular movement causes the pressure exerted by a gas and hence derive the relationship pV = ⅓ Nm<c²>, where N is the number of gas molecules (a simple model considering one-dimensional collisions and then extending to three dimensions using ⅓ <c²> = <cx²> is sufficient).

(h) Recall and apply the relationship that the mean kinetic energy of a molecule of an ideal gas is proportional to the thermodynamic temperature (i.e. ½ m<c²> = 3/2 kT) to new situations or to solve related problems.