A student measures the energy released as water cools in an insulated beaker. The water has a mass of 0.25 kg and a specific heat capacity of 4200 J/kg ∘C4200\ \mathrm{J/kg}\,{}^\circ\mathrm{C}4200 J/kg∘C. Its temperature is initially uniform at 80 ∘C80\ ^\circ\mathrm{C}80 ∘C. After cooling, the student records these temperatures:
| Measurement | Temperature |
|---|---|
| Near the surface, before stirring | 60 ∘C60\ ^\circ\mathrm{C}60 ∘C |
| After stirring | 57 ∘C57\ ^\circ\mathrm{C}57 ∘C |
Calculate the energy released by the water using the temperature after stirring. Explain how using the reading near the surface before stirring would affect the calculated energy released.
110 exam-style questions on Edexcel GCSE Physics 14.2 Specific heat capacity and latent heat, covering 14.2.1 Heating, temperature and changes of state, 14.2.2 Specific heat capacity and specific latent heat, 14.2.3 Specific heat capacity calculation, 14.2.4 Specific latent heat calculation, and 14.2.5 Reducing energy transfer through thermal insulation. Each one has a worked solution and a mark scheme showing where the marks go.