Whereas an object appears black when no light is reflected or when no light reaches the eye. Therefore all the colors are absorbed. Silver is the best reflector of light in the visible spectrum, not every spectrum. Black color absorbs more light in comparison to other color. And if the surface is rough then it has large surface area in comparison to smooth surface and less reflection so the heat is more absorbed in this case.
When infrared radiation hits an object some of the energy is absorbed, making the objects temperature increase, and some is reflected.
Light, shiny surfaces are poor absorbers and emitters of infrared radiation. The new black surface may be better at radiating the heat but the heat still has to be transferred from the shiny surface to the black paint before it can be radiated from the black paint. Surely adding any layer to the outside of a radiator will reduce its ability to radiate heat.
Completing the other answer, radiator color only has a direct impact on the emitted wavelengths of the radiator. Shiny surfaces are poor absorbers and emitters but they are good reflectors of infrared radiation. If two objects made from the same material have identical volumes, a thin, flat object will radiate heat energy faster than a fat object. This is one reason why domestic radiators are thin and flat.
Radiators are often painted with gloss paint, but they would be better at radiating heat if they were painted with matt paint instead. Your email address will not be published. SmartStudy Solutions is an independent company and has not been authorised, sponsored, or otherwise approved by the Caribbean Examinations Council.
Home Prep for success Reviews. Antonia Warren Author archive. Previous post Next post. Long wavelength heat radiation in the far infra red does not travel through glass. Heat radiation is absorbed better by black surfaces than by shiny ones You can show this last property by sticking a thin piece of aluminium foil on the back of your hand and testing the heat received from the heater. If you now paint the foil black using carbon black dissolved in meths and test the heat again you will find that it feels much hotter than without the black although the heater was giving out the same amount of heat radiation in both cases.
This classic piece of apparatus was devised to show the difference between the absorption of heat radiation by black and silvered surfaces. When heat radiation falls on the vane the black sides absorb heat better than the shiny sides, this means that they hat up more quickly.
The air next to the black sides heats up, expands and so pushes the vane round. Leslie's cube is a metal box with four differently painted sides. If it is filled with boiling water from a kettle you can use either your hands or a thermopile connected to a meter to try and decide which surfaces give out the most heat radiation.
Heat radiation is rays or waves of heat energy. In spite of what some people think, wearing clothes of different colours does not make a lot of difference to how well we can loose heat.
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