Four different blocks are heated to the same high temperature. Which block emits thermal radiation at the fastest rate?
| Colour and texture of surface | Surface area / cm2\text{cm}^2cm2 | |
|---|---|---|
| A | shiny silver | 40 |
| B | shiny silver | 160 |
| C | dull black | 40 |
| D | dull black | 160 |
Shiny silver surface with surface area 40 cm240\text{ cm}^240 cm2
Shiny silver surface with surface area 160 cm2160\text{ cm}^2160 cm2
Dull black surface with surface area 40 cm240\text{ cm}^240 cm2
Dull black surface with surface area 160 cm2160\text{ cm}^2160 cm2
301 exam-style questions on CIE IGCSE Physics 2.3 Transfer of thermal energy, covering 2.3.1a Thermal conductors and thermal insulators, 2.3.1b Explaining thermal conduction, 2.3.2 Convection, 2.3.3a Thermal radiation, 2.3.3b Surface colour and texture, 2.3.3c Rate of emission and absorption of radiation, and 2.3.4 Consequences of thermal energy transfer. Each one has a worked solution and a mark scheme showing where the marks go.