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Thermal Physics

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does the first law of thermodynamics account for the energy of a system in terms of heating and work done?

Define internal energy as the sum of molecular kinetic and potential energies, and apply the first law of thermodynamics to changes in a gas
A focused answer to the H2 Physics learning outcome on internal energy and the first law. Internal energy as molecular kinetic plus potential energy, the first law sign conventions, and applying it to isothermal, isobaric and adiabatic gas changes.
9 min answer →

How does the kinetic model of a gas connect microscopic molecular motion to the macroscopic pressure, volume and temperature?

State the assumptions of the kinetic theory of an ideal gas, apply the ideal gas equation, and relate pressure and temperature to the mean square molecular speed
A focused answer to the H2 Physics learning outcome on the kinetic theory of gases. The model assumptions, the ideal gas equation, the pressure relation pV = (1/3)Nm<c^2>, and the link between temperature and mean molecular kinetic energy.
9 min answer →

Why do different substances need different amounts of energy to change temperature or state, and how do we calculate that energy?

Define and apply specific heat capacity and specific latent heat to calculate energy transfers during temperature changes and changes of state
A focused answer to the H2 Physics learning outcome on specific heat capacity and specific latent heat. The defining equations, why latent heat involves no temperature change, and multi-stage heating and phase-change calculations.
8 min answer →

What does temperature actually measure, and what does it mean for two bodies to be in thermal equilibrium?

Define thermal equilibrium and thermodynamic temperature, relate the kelvin and Celsius scales, and explain temperature as a measure of average molecular kinetic energy
A focused answer to the H2 Physics learning outcome on temperature. Thermal equilibrium and the zeroth law, the thermodynamic (kelvin) scale, its link to Celsius, and temperature as a measure of average molecular kinetic energy.
7 min answer →

How do pressure-volume processes and the first law combine to describe the work output of a gas in a thermodynamic cycle?

Represent thermodynamic processes on a pressure-volume diagram, calculate the work done by a gas as the area under the curve, and analyse a simple cycle
A focused answer to the H2 Physics learning outcome on thermodynamic processes. Reading pressure-volume diagrams, computing work as the area under the curve, the four standard processes, and the net work of a closed cycle.
8 min answer →