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प्रश्न
If the back of your hand is moistened with alcohol, you will find that it rapidly becomes dry. Why is it that while it is drying, your hand feels cool ?
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उत्तर
Alcohol is a volatile liquid. It evaporates very fast by absorbing heat from surroundings. When our hand is moistened with alcohol, drops of alcohol absorb heat from the hand to achieve latent heat of vaporization and evaporate. As the hand loses heat to alcohol, it feels cool. This is an example of cooling by evaporation.
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संबंधित प्रश्न
Why does a desert cooler cool better on a hot dry day?
State three factors which affect the rate of evaporation of a liquid.
Give two applications of evaporation.
How does the water kept in an earthen pot (matka) become cold during summer ?
How will you demonstrate that water vapour is present in air ?
What is evaporation ? State the various factors which affect evaporation.
During summer days, water kept in an earthen pot (pitcher) becomes cool because of the phenomenon of :
The evaporation of water increases under the following conditions :
How does the water kept in an earthen pot remain cool?
Comment on the following statements:
Evaporation produces cooling.
