Physics Question & Answers
Hot water is poured simultaneously in four metallic tumblers painted outside with different paints. After some time the water will be found to have cooled most in the tumbler painted.
|A) rough white||B) rough black|
|C) shining white||D) shining black|
Black surfaces are good emitters of heat. If the black surface is rough too, the emitting will be better. Shinning surfaces reflect black radiation . So if the black surface is also shining the effectiveness of emitting heat is lessened.
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