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प्रश्न
Write true or false
A natural change can also be a desirable change.
विकल्प
True
False
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उत्तर
True
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Passing of electric current through water, and water breaking down into hydrogen and oxygen gases.
Tick the most appropriate answer.
5. Photosynthesis requires
- heat energy.
- wind energy
- sunlight.
- sound energy
Dissolving salt in water is a reversible change.
Photosynthesis cannot take place at night.
What role does energy play in initiating a chemical change ?
Write true or false
Rusting of iron is a chemical change.
Fill in the blank.
A change, which alters the composition of a substances, is known as a___________ 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. |
Physical Change: Boiling::Chemical Change: ______.
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
