Why do people sprinkle water on the roof-top after a hot sunny day?

Introduction:
After a hot sunny day, people often sprinkle water on the roof-top to provide relief from the heat. This practice has been followed for centuries and has proven to be effective in cooling down the temperature of the roof and the surrounding area. The correct answer to why people sprinkle water on the roof-top is option 'D' - water has a large latent heat of vaporization. Let's delve deeper into this explanation.

Explanation:
Sprinkling water on the roof-top helps in cooling down the area due to the following reasons:

1. Latent Heat of Vaporization:
Water has a large latent heat of vaporization, which means it requires a significant amount of heat energy to change from a liquid state to a vapor (gas) state. When water is sprinkled on the roof-top, the heat from the surroundings is absorbed by the water. This heat energy is used to convert the liquid water into water vapor. As a result, the roof and the surrounding air experience a cooling effect.

2. Evaporative Cooling:
The process of water evaporating cools down the surroundings. When water is sprinkled on the roof-top, it gradually evaporates into the air. During evaporation, the water molecules gain enough energy to break free from the liquid phase and enter the gaseous phase. This process requires heat energy, which is extracted from the surroundings, including the roof-top and the air around it. As a result, the temperature of the roof and the surrounding area decreases.

3. Heat Absorption:
Water has a higher specific heat capacity compared to many other substances. Specific heat capacity is the amount of heat energy required to raise the temperature of a substance by a certain amount. As water is sprinkled on the roof-top, it absorbs heat from the surrounding environment, including the hot roof and the air. This absorption of heat helps in reducing the temperature of the roof and the surrounding area.

4. Easy Availability and Accessibility:
Another reason why people choose to sprinkle water on the roof-top is because water is easily available and accessible. It is a cost-effective and simple method to cool down the area without the need for complicated machinery or equipment.

Conclusion:
In conclusion, people sprinkle water on the roof-top after a hot sunny day because water has a large latent heat of vaporization, which allows it to absorb heat energy from the surroundings and provide a cooling effect. Additionally, water's high specific heat capacity and easy availability make it an ideal choice for cooling down the roof and the surrounding area.