20. 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
Option B Solution: 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 rough black. Black surfaces are good emitters of heat.
