# Physics Topic: Thermal Physics

Show an understanding that internal energy is determined by the state of the system and can be expressed as the sum of a random distribution of kinetic and potential energies associated with the molecules of the system.

Relate a rise in temperature of a body to an increase in its internal energy.

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

Show an understanding that there is an absolute scale of temperature which does not depend on the property of any particular substance i.e. the thermodynamic scale.

Apply the concept, on the thermodynamic (Kelvin scale), absolute zero is the temperature at which all substances have a minimum internal energy

Convert temperatures measured in Kelvin to degrees Celsius:

*T*/K =*Theta*/^{o}C + 273.15.Define and use the concept of specific heat capacity, and identify the main principles of its determination by electrical methods.

Define and use the concept of specific latent heat, and identify the main principles of its determination by electrical methods.

Explain using a simple kinetic model for matter why:

- melting and boiling take place without a change in temperature,
- the specific latent heat of vaporisation is higher than specific latent heat of fusion for the same substance,
- cooling effect accompanies evaporation.

Recall and use the first law of thermodynamics expressed in terms of the change in internal energy, the heating of the system and the work done on the system.

Recall and use ideal gas equation

*pV = nRT*where*n*is the amount of gas in molesShow an understanding of the significance of the Avogadro constant as the number of atoms in 0.012 kg of carbon-12.

Use molar quantities where one mole of any substance is the amount containing a number of particles equal to the Avogadro constant.

Recall and apply the relationship that the mean kinetic energy of a molecule of an ideal gas is proportional to the thermodynamic temperature to new situations or to solve related problems.