Advertisements
Advertisements
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 ?
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.
APPEARS IN
संबंधित प्रश्न
How does water kept in an earthen pot (matka) become cool during summer?
Explain why in hot summer days water remains cool in earthen pots.
Why is heat energy needed to melt a solid ? What is this heat energy called ?
How does the water kept in an earthen pot (matka) become cold during summer ?
Why are we able to sip hot tea or milk faster from a saucer rather than from a cup ?
Why does our palm feel cold when we put some acetone (or perfume) on it ?
The ______ of air is dependent on the temperature of air.
Evaporation is a fast process and occurs only at the surface of the liquid.
When lemon juice is mixed with soda water, they produce brisk effervescence.
The process of evaporation is not a good technic to separate salt from seawater give a reason.
