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प्रश्न
Which of the following are physical changes ?
- melting of iron metal
- rusting of iron metal
- bending of an iron rod
- drawing a wire of iron metal
पर्याय
(i), (ii) and (iii)
i), (ii) and (iv)
(i), (iii) and (iv)
(ii), (iii) and (iv)
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उत्तर
(i), (iii) and (iv)
The process in statement (ii) is a chemical change because rusting causes formation of a new compound. Other statements are examples of physical changes where no new compounds are formed. In the process mentioned in other statements, original form of iron can be obtained back from moulded forms.
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संबंधित प्रश्न
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 for the statement.
Deforestation is a man-made change
Give two examples of periodic changes.
Sublimation is classified as a physical change. Why ?
Give a reason why
Change of seasons is a periodic change while the change of weather is a non-periodic change.
Select the chemical changes from the following list of changes
The crystallisation of salt from its solution.
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.
Name the following.
The gaseous product of the chemical change which takes place during respiration in living organisms.
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Do you think rust is different from iron?
