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प्रश्न
How will you demonstrate that water vapour is present in air ?
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उत्तर
The presence of water vapour in air can be shown by the following experiment:
Take a steel tumbler and put some well-crushed ice into it and wipe its surface with a clean dry cloth, so as to make its surface completely dry. Allow it to stand for 5 minutes. A large number of drops of water vapour appear on the outer surface of the tumbler. This happens because the air around the steel tumbler contains water vapour in it. When this water vapour comes into contact with the cold outside surface of the steel tumbler, it condenses to form tiny drops of liquid water. The formation of tiny drops of water outside the steel tumbler containing crushed ice, shows the presence of water vapour in air.
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संबंधित प्रश्न
Why does a desert cooler cool better on a hot dry day?
What is evaporation?
Wet clothes dry more quickly on a warm dry day than on a cold humid day. Explain.
Why does all the water of the earth not get evaporated during hot summer days ?
Why does our palm feel cold when we put some acetone (or perfume) on it ?
The amount of vapour in 1 cu.m. of air shows the ______.
How is humidity measured?
Evaporation of water from lakes and river ______.
Comment on the following statements:
Evaporation produces cooling.
Evaporation is a fast process and occurs only at the surface of the liquid.
