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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 |
Water changes into ice on cooling is an example of ______.
Changes which cannot be reversed are called ______.
Water on ______ changes to ice and on ______ comes back to water.
While lighting a candle, Paheli observed the following changes.
- Wax was melting
- Candle was burning
- Size of the candle was reducing
- Melted wax was getting solidified.
Of the above, the changes that can be reversed are
Salt can be separated from its solution (salt dissolved in water), because ______.
Which of the following changes cannot be reversed?
- Blowing of a balloon
- Folding paper to make a toy aeroplane
- Rolling a ball of dough to make roti
- Baking cake in an oven
- Drying a wet cloth
- Making biogas from cow dung
- Burning of a candle
Give one example of change which occurs on cooling but can be reversed.
Give one example of change occurs on mixing two substances, but can be reversed.
Give one example of change which occurs on mixing two substances, but cannot be reversed.
