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प्रश्न
Select the chemical changes from the following list of changes
Glowing of an electric bulb.
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उत्तर
Glowing of an electric bulb is a PHYSICAL change as no change in the composition of filament takes place is reversible, the only filament glows when electricity is passed and returns to its original form on switching off the electric current.
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संबंधित प्रश्न
Try segregating the things around you as pure substances or mixtures.
Match the columns
| column A | coulmn B |
| 1. A change which cannot be easily reversed | a. man-made change |
| 2.A change that repeats itself at regular intervals | b. chemical change |
| 3. A change that is made by humans | c. physical change |
|
4. A change in which the original substance cannot be obtained |
d. periodic change |
| 5. A change where no new substance is formade | e. irreversible change |
| f. slow change |
Write true or false
Burning of paper and formation of curd are reversible changes.
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.
Slow and fast 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.
State whether the following statement is true or false. If false write the correct statement.
Melting of butter and wax are examples of chemical changes.
Give a reason why – Addition of zinc nitrate to water is a physical change but, the addition of zinc to dilute nitric acid is a chemical change.
Select the correct answer from the choice given below to complete the sentence
A change in which a substance retains its identity is a
______ change.
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
Sublimation of Iodine is a ______.
