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प्रश्न
Give reason.
A dry handkerchief gets wet at once on dipping in water, but it takes longer for a wet handkerchief to dry.
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उत्तर
A dry handkerchief gets wet at once because it quickly absorbs the water in which it is dipped. However, it takes longer for a wet handkerchief to dry because the water needs to evaporate from the handkerchief. Evaporation is a slow process that is dependent on other factors as well, like relative humidity.
संबंधित प्रश्न
What do you observe when :
solid ammonium chloride is heated
State whether the following is physical or chemical changes.
Boiling of an egg —
True or false?
During a physical change energy is either given out or absorbed by the system.
Fill in the blank
An earthquake is a _______ change.
Give reason.
While purchasing canned food, its expiry date should be checked.
Explain in brief the involvement of energy in physical and chemical changes.
Fill in the blanks with the appropriate words of the statement given below:
Chemical changes may involve exchange of energy in the form of __________ and _________.
Fill in the blank with the correct word of the statement given below:
Ammonium chloride, a sublimable solid undergoes _________ on heating.
Observe the picture containing a kettle and note that it has salt water in it and answer the following questions:
- What is name of the process that is done to the kettle?
- What will happen to the content of the kettle?
- What kind of change is occurring on the cold surface of the metal plate?
- What can you say about the quality of water that is obtained in the beaker?
What is the change?
