Two identical heated storage cabinets are in the same room. Each cabinet has one removable wall panel. The panels are made from different insulating materials but have the same thickness.
The heaters are switched off. The table shows the time at which the air inside each cabinet reaches two temperatures.
| Panel | Time to reach 70 ∘C70\ ^\circ\mathrm{C}70 ∘C in min | Time to reach 50 ∘C50\ ^\circ\mathrm{C}50 ∘C in min |
|---|---|---|
| P | 2 | 18 |
| Q | 4 | 24 |
Calculate the mean rate of temperature decrease between 70 ∘C70\ ^\circ\mathrm{C}70 ∘C and 50 ∘C50\ ^\circ\mathrm{C}50 ∘C for each cabinet. Give your answers in ∘C/min^\circ\mathrm{C}/\mathrm{min}∘C/min.
Which panel is more effective at reducing the energy transferred out of the cabinet? Give a reason for your answer.
Suggest how making panel Q thicker would affect the cooling of its cabinet.
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.