QUESTION #136

Will a black container of hot water lose heat faster or slower than a white container of hot water?

Asked by: Katy Ward

Answer

A black body is assumed to be a perfect radiator of heat.

A black container of water can be said to be closer to a black body than a white container. Kirchoff's laws of radiation make it evident that a BLACK BODY IS NOT ONLY A PERFECT ABSORBER BUT ALSO A PERFECT emitter of heat. Hence the black container will cool down faster.

Wear a black cotton shirt in summer, you'll sweat!
Wear a cotton (black) shirt in winter you'll freeze!
Answered by: Akhilesh, Undergrad, India