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प्रश्न
Tick the most appropriate answer.
Photosynthesis requires
पर्याय
heat energy
wind energy
sunlight
sound energy
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उत्तर
sunlight.
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संबंधित प्रश्न
Tick the most appropriate answer
2. Melting of ice is a
- reversible change
- irreversible change
- chemical change
- none of these
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 short answer.
What are man-made changes ?
State the various conditions that favour the process of evaporation.
What are man-made changes ?
Differentiate between a physical change and a chemical change with reference to – Nature of change is temporary and reversible or permanent and irreversible.
Ice kept in a beaker, slowly melts and turns into water. The water in the beaker on solidification is freezing turns back to ice. Give four reasons why the change from ice to water and water back to ice is considered a physical change.
Give a reason why – Heating a platinum wire is a reversible change but, heating a magnesium wire is an irreversible change.
When a woolen yarn is knitted to get a sweater, the change can be classified as ____________.
Sublimation of Iodine is a ______.
