Two identical metal cans are filled with equal amounts of cold water at the same temperature. One can is painted dull black, while the other has a shiny silver surface. Both cans are placed at the same distance from a radiant electric heater. After several minutes, the temperature of the water in the dull black can is found to be higher than that in the shiny silver can. Why does the water in the dull black can warm up more quickly?
Dull black surfaces are better conductors of heat than shiny silver surfaces.
Dull black surfaces are better absorbers of thermal radiation than shiny silver surfaces.
Dull black surfaces are better reflectors of thermal radiation than shiny silver surfaces.
Dull black surfaces are worse emitters of thermal radiation than shiny silver surfaces.
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.