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प्रश्न
What is a physical change ? Give two examples of physical changes.
उत्तर
Physical change: These are changes in which no new substances are formed. These are temporary changes, which are easily reversible. The substance, which is involved in a physical change, does not lose its identity.
Examples:
- Water, if boiled, can be cooled and condensed.
- Mixing of iron fillings with sand is a physical change because they can be separated by a magnet.
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संबंधित प्रश्न
Which of the following are chemical changes?
- Growth of a plant
- Rusting of iron
- Mixing of iron fillings and sand
- Cooking of food
- Digestion of food
- Freezing of water
- Burning of candle
Define physical change. Give two examples for the above changes.
State whether the following is physical or chemical changes.
burning of sugar —
Give two examples of periodic changes.
State the various conditions that favour the process of evaporation.
Classify the following as physical or chemical changes :
- Cooking of food
- Boiling of water
- Cutting of trees
- D0issolving salt in water
- Digestion of food
- Melting of ice
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.
Periodic and non-periodic change
Give a reason why – Heating a platinum wire is a reversible change but, heating a magnesium wire is an irreversible change.
Select the correct answer from the choice given below to complete the sentence
The matter is added or removed during a ____________ change.
Mention some of the different conditions needed for chemical changes to occur.
