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प्रश्न
Why does a lump of cotton wool shrink in water?
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उत्तर
A lump of cotton wool shrinks when immersed in water. This is because air present in the cotton wool escapes. Thus, the volume of the cotton wool decreases.
संबंधित प्रश्न
Answer the question put against the following constituents of air :
Oxygen : What is the percentage proportion of oxygen in air ? Why is oxygen called active air.
Statement given below is incorrect. Write the correct statement :
During thunder and lightning, nitrogen and oxygen combine to form nitrogen dioxide gas.
Briefly state the importance of Oxygen.
Tick (√ ) the most appropriate answer.
Magnesium burns with a dazzling white flame to form magnesium oxide, a powdery mass. The colour of magnesium oxide is :
Give reason:
A burning candle stops burning if covered with a glass tumbler
Complete the statement given below by filling in the blank with the correct word from the words given:
The component of air used in photosynthesis is ______ and the products of photosynthesis is oxygen.
What is the source of carbon dioxide in air?
Nitrogen is _______ than air.
______ is the main component of air.
______ is responsible for making clouds.
