An electric kettle contains boiling water. The heating element is made of copper, and the handle is covered with plastic.
Explain, in terms of atomic lattice vibrations and free electrons, how thermal energy is conducted through the copper heating element.
As the water boils, it continues to absorb thermal energy, but its temperature remains constant at 100∘C100^\circ\text{C}100∘C. Explain this observation in terms of molecules, intermolecular attractive forces, and potential energy.
The mass of the water in the kettle decreases by 0.12 kg0.12\text{ kg}0.12 kg in a time of 180 s180\text{ s}180 s due to vaporisation. The specific latent heat of vaporisation of water is 2.25×106 J/kg2.25 \times 10^6\text{ J/kg}2.25×106 J/kg.
Calculate the rate at which the water is gaining thermal energy.
528 exam-style questions on CIE IGCSE Physics 2.2 Thermal properties and temperature, covering 2.2.1 Thermal expansion of solids, liquids and gases, 2.2.2a Internal energy and temperature, 2.2.2b Specific heat capacity, 2.2.3a Melting, boiling, condensation and solidification, 2.2.3b Evaporation, and 2.2.3c Cooling by evaporation. Each one has a worked solution and a mark scheme showing where the marks go.