Four garden sheds, A, B, C and D, are the same size and shape. On a cold day, each shed is heated to the same temperature and then the heater is switched off.
The Table shows the material and thickness of the walls of each shed.
Table
| Shed | Wall material | Thickness of walls in cm\text{cm}cm |
|---|---|---|
| A | concrete | 10 |
| B | concrete | 20 |
| C | wood | 20 |
| D | wood | 10 |
Concrete has a higher thermal conductivity than wood.
Which shed, A, B, C or D, cools fastest?
Which shed, A, B, C or D, cools most slowly?
Explain your answer.
Sheds B and D cool at almost the same rate.
Suggest why.
50 exam-style questions on OCR GCSE Physics 7.2 Power and efficiency, covering 7.2.1 Dissipation of energy, 7.2.2 Energy transfers in domestic devices, 7.2.3 Power ratings of domestic appliances, 7.2.4 Efficiency of energy transfers, 7.2.5 Ways to increase efficiency, 7.2.6 Reducing unwanted energy transfers, and 7.2.7 Thermal conductivity and the cooling of buildings. Each one has a worked solution and a mark scheme showing where the marks go.