Why is black colour good absorber and radiator of heat ?

AI Thread Summary
Black objects absorb nearly all frequencies of light, leading to a significant increase in energy and heat compared to lighter colors, which reflect most light. This property explains why dark colors are avoided in summer, as they can cause materials like ice to melt more quickly. The discussion emphasizes that the definition of black is tied to its lack of light reflection, making it a good absorber and radiator of heat. Understanding these principles clarifies why black surfaces can become much hotter than white ones. Overall, the absorption of light by black objects results in higher heat production.
sankalpmittal
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I have read in my class 10th book and other books that black(usually dark) colour is avoided in summers and this is the reason why impure ice melts quickly .

I am wondering why ?
 
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The color of any object is the light it reflects. An object is white if it reflects all or almost all of the light falling on it (and so absorbs little light). An object is black if it reflects no or very little light (and so absorbs almost all light). And, of course, light is energy. Absorbing little light only a slight increase in energy, absorbing a lot of light means a larger increase in energy and so a larger increase in heat.
 
russ_watters said:
By definition of the word "black".

Why is black colour good absorber and radiator of heat ? (usually dark colours)

How ? By definition ??
 
HallsofIvy said:
The color of any object is the light it reflects. An object is white if it reflects all or almost all of the light falling on it (and so absorbs little light). An object is black if it reflects no or very little light (and so absorbs almost all light). And, of course, light is energy. Absorbing little light only a slight increase in energy, absorbing a lot of light means a larger increase in energy and so a larger increase in heat.

Yes you are absolutely correct but why black colour absorbs large amount of light as compared to white .
 
russ_watters said:
By definition of the word "black".

HallsofIvy said:
The color of any object is the light it reflects. An object is white if it reflects all or almost all of the light falling on it (and so absorbs little light). An object is black if it reflects no or very little light (and so absorbs almost all light). And, of course, light is energy. Absorbing little light only a slight increase in energy, absorbing a lot of light means a larger increase in energy and so a larger increase in heat.

Got you ! Thanks russ_watters . The answer to this question was by definition of word black .

Black is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light. Although black is sometimes described as an "achromatic", or hueless, color, in practice it can be considered a color, as in expressions like "black cat" or "black paint".
http://en.wikipedia.org/wiki/Black


So black absorbs all the frequencies of light and doesn't reflect so more heat is produced in that , right .


Thanks to you all who replied .:smile:
 
sankalpmittal said:
So black absorbs all the frequencies of light and doesn't reflect so more heat is produced in that , right .
Yes.
 
Redbelly98 said:
Yes.

OK Thanks .
 

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