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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 :
a piece of paper is burnt
What do you observe when :
a spoon of sugar is heated in a pan
Fill in the blank
Burning of fuel is a _______ change.
State whether the following is physical or chemical changes.
Boiling of an egg —
Distinguish between the following.
Periodic change and non-periodic change
Distinguish between the following.
Natural change and man-made change
Under which different types can the following changes be classified?
Conversion of milk into yoghurt.
Give reason.
While purchasing canned food, its expiry date should be checked.
Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.
| S. No. | Change | Can be reversed (Yes/No) |
| 1. | The sawing of a piece of wood | |
| 2. | The melting of ice candy | |
| 3. | Dissolving sugar in water | |
| 4. | The cooking of food | |
| 5. | The ripening of a mango | |
| 6. | Souring of milk |
Paper, LPG, CNG petrol, etc, are ______ substances.
