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प्रश्न
When a candle is lit the following changes are observed.
- Wax melts.
- Candle keeps burning.
- The size of the candle decreases.
- The molten wax solidifies
- Which of the changes can be reversed? Justify your answer
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उत्तर
- Wax melting is a reversible change.
- “The molten wax solidifies” is a reversible change.
These two changes can be reversible to get back to the original state. So the above two changes are reversible changes.
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संबंधित प्रश्न
Very Short Answer Type Question:
Some common changes are given in the below Table. Which of these changes do you think can be reversed?
| Change | Can be reversed |
| (i) Raw egg to boiled egg | Yes/No |
| (ii) Batter to idli | |
| (iii) Wet clothes to dirty clothes | |
| (iv) Woollen yarn to knitted sweater | |
| (v) Grain to its flour | |
| (vi) Cold milk to hot milk | |
| (vii) straight string to a cold string | |
| (viii) Bud to flower | |
| (ix) Milk to paneer | |
| (x) Cow dung to biogas | |
| (xi) stretched rubber band to its normal size | |
| (xii) Melting of ice-cream |
Long Answer Type Question:
Explain how a metal rim slightly smaller than a wooden wheel can be fixed on it.
To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Changes which cannot be reversed are called ______.
Salt can be separated from its solution (salt dissolved in water), because ______.
Can we reverse the following change? If yes, suggest the name of the method.
Ice into water
Boojho’s sister broke a white dove, a symbol of peace, made of Plaster of Paris (POP). Boojho tried to reconstruct the toy by making a powder of the broken pieces and then making a paste by mixing water. Will he be successful in his effort? Justify your answer.
Tearing of paper is said to be a change that cannot be reversed. What about paper recycling?
Change of a bud into a flower is a change which cannot be reversed. Give four more such example.
Choose the odd one out. Give reason for your choice.
