When water is sprinkled on a hot surface like a rooftop, it evaporates. Evaporation is a process that requires energy (heat). This energy is absorbed from the surroundings, including the rooftop itself and the air, as the water changes from liquid to gas phase. The latent heat of vaporisation is the amount of heat energy required to change a substance from a liquid to a gas at a constant temperature. Water has a relatively high latent heat of vaporisation, meaning it absorbs a significant amount of heat from the rooftop during evaporation, leading to a substantial cooling effect.
After a hot sunny day, people sprinkle water on the roof-top because :
Asked in UPSC CDS 1 2016 · Topic: Heat and Thermodynamics (Calorimetry and Phase Changes (Specific Heat, Latent Heat))
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Answer: D. water has large latent heat of vaporisation
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