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प्रश्न
A drawing sheet changes when you draw a picture on it. Can you reverse this change?
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उत्तर
If we draw a picture on a drawing sheet with a pencil, we can get back the original drawing sheet by erasing the drawing with an eraser. In this case, the change can be reversed.
However, if we draw with a pen, then the original drawing sheet cannot be obtained back because we cannot erase ink. Hence, in this case, the change cannot be reversed.
संबंधित प्रश्न
Drying of wet clothes in air is an example of
Burning of match stick is a reversible change.
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
Look at the figure which shows three situations.
Which of these shows a reversible change and why?
Can we reverse the following change? If yes, suggest the name of the method.
Water into water vapour
Can we reverse the following change? If yes, suggest the name of the method.
Ice into water
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 mixing two substances, but cannot be reversed.
Conversion of ice into water and water into ice is an example of change which can be reversed. Give four more examples where you can say that the changes can be reversed.
Choose the odd one out. Give reason for your choice.
