Option 1: Water helps air around the roof-top to absorb the heat instantly.
This option is not correct. While water can help cool down the air by absorbing heat, it is not instantaneous. The process of evaporation takes time and requires energy.
Option 2: Water has lower specific heat capacity.
This option is not correct. Water actually has a high specific heat capacity, which means it takes a relatively large amount of heat energy to raise its temperature. It is because of this property that water is commonly used in cooling systems to absorb and transfer heat.
Option 3: Water is easily available.
This option is not the main reason for sprinkling water on the roof-top after a hot sunny day. While water may be easily available, it is not the sole reason for this practice.
Option 4: Water has a large latent heat of vaporization.
This option is the correct answer. Water has a high latent heat of vaporization, which means it requires a significant amount of energy to change from a liquid to a gas. When water evaporates from the roof-top, it absorbs heat from the surroundings, cooling down the surface of the roof-top and the air around it.
In conclusion, sprinkling water on the roof-top after a hot sunny day is done