A brass key has a thermal capacity of 8.5 J/∘C8.5\text{ J}/^\circ\text{C}8.5 J/∘C.
Explain what is meant by thermal capacity.
The brass key is dropped into a beaker of boiling water. The internal energy of the key increases as its temperature increases from 18∘C18^\circ\text{C}18∘C to 100∘C100^\circ\text{C}100∘C.
Calculate the increase in the internal energy of the key.
State, in terms of the atoms, what is meant by internal energy.
The key is removed from the boiling water and immediately begins to transfer energy to the surroundings. The temperature of the surroundings is 18∘C18^\circ\text{C}18∘C.
Describe the three key features of a graph of temperature against time for the key from the instant it is removed from the water.
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.