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प्रश्न
Change is the law of nature and occurs in our everyday life, at all times and in all places. Differentiate between the following change with a suitable example.
Desirable and undesirable change.
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उत्तर
| Desirable change | Undesirable change |
| (i) Changes brought about by nature or man which produces – useful or good results. | (i) Changes brought about by nature or man which produces – useless or bad results. |
| (ii) Positive and advantageous nature. | (ii) Negative and detrimental nature. |
| (iii) Examples of a desirable change: Rain bringing water to the crops, change of milk to curd, ripening of fruits seedling into a plant. |
(iii) Examples of an undesirable change: Rain causing destruction by floods, milk turning sour on a hot day, rotting of fruits, cutting of trees. |
APPEARS IN
संबंधित प्रश्न
Write true or false for the statement.
Burning of paper and formation of curd are reversible changes
State whether the following is physical or chemical changes.
(energy produced) dissolving sugar in water —
Write true or false
Deforestation is a man-made change.
Classify the following as physical or chemical change :
Condensation of steam
Given reason:
Burning of paper is a chemical change.
Give reasons why – separation of mixtures e.g. iron from a mixture of iron and sulphur is a physical change, but heating a mixture of iron and sulphur is considered a chemical change.
Match the examples of changes in List I with the correct.
| List I | List II |
| 1. Expansion of a steel rod on heating | A: Physical change |
| 2. Rotting of eggs | B: Chemical change |
| 3. Milk turning sour | |
| 4. Tarnishing of copper | |
| 5. Separation of naphthalene from a mixture of naphthalene and sodium chloride. |
Stretching gold coin into a ring is a ______ change.
______ is the Universal Solvent.
Explain the characteristics of physical change with examples.
