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प्रश्न
Write a few lines on the blackboard with a chalk. Now observe the chalk. What changes do you see in the chalk?
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उत्तर
The chalk reduces in size after writing on the blackboard. It becomes flat on the side from which we use it for writing.
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संबंधित प्रश्न
Gases have definite volume but no definite shape.
Give one difference between atoms and molecules.
What is the scientific name of particles which make up mater?
Give reason why graphite is used for making elecrode in a dry cell.
Name a non-metal :
- which is lustrous
- which is required for combustion
- whose one of the allotrophic forms is a good conductor of electricity. Name the allotrope.
- other than carbon which shows allotropy
- which is known to form the largest number of compounds
What are (i) metals (ii) non-metals, and (iii) metalloids ? Give two examples each of metals, non-metals and metalloids.
Which one of the following is not a chemical change ?
Explain how, nitrogen , oxygen and argon gases are separated from air.
The non S I and S I units of some physical quantities are given in column A and column B respectively. Match the units belonging to the same physical quantity:
| (A) | (B) | ||
| (a) | degree celsius | (i) | kilogram |
| (b) | centimetre | (ii) | pascal |
| (c) | gram per centimetre cube | (iii) | metre |
| (d) | bar | (iv) | kelvin |
| (e) | milligram | (v) | kilogram per metre cube |
Give an example of liquid in gas.
