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प्रश्न
What do you observe when a burning candle is covered with an inverted jar.
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उत्तर
The burning of a candle needs a continuous supply of oxygen present in the air. By covering the candle with a jar, the supply of oxygen gets cut, and as there is only a limited quantity of oxygen left, the candle burns for a moment and then goes off completely.
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संबंधित प्रश्न
Match the statements in Column A, with those in Column B.
| Column A | Column B |
| 1. Largest Constituent of air, which dilutes the activity of oxygen. | (a) Oxygen |
| 2. A gas used for filling weather observeation balloons. | (b) Carbonic acid |
| 3. An acid formed by the dissolution of sulphur dioxide gas in water. | (c) Sulphuric acid |
| 4. An acid formed by the dissolution of carbon dioxide in water. | (d) Helium |
| 5. A gas vital for respiration. | (e) Nitrogen |
Write ‘True’ or ‘False’ in front of following statement.
Atmospheric nitrogen is directly absorbed by the plants to form plant proteins.
Fill in the blank:
_____________ discovered the oxygen gas.
Match the statements in Column A, with those in Column B.
| Column A | Column B |
| 1. Largest Constituent of air, which dilutes the activity of oxygen. |
(a) Oxygen |
| 2. A gas used for filling weather observation balloons. | (b) carbon acid |
| 3. An acid formed by the dissolution of sulphur dioxide gas in water. | (c) Sulphur acid |
| 4. An acid formed by the dissolution of carbon dioxide in water. | (d) Helium |
| 5. A gas vital for respiration. | (e) Nitrogen |
What do you observe when a beam of light is allowed to enter in a closed dark room through a small hole.
Name two important processes supported by oxygen present in air.
How is air useful to agriculture?
What is meant by the term ‘atmosphere’? State the role played by the atmosphere for the survival of mankind.
State whether the following statement is true or false.
The pressure exerted by air is called atmospheric pressure.
Explain the term ‘air pollution’, with reference to air quality. State the sources of a few main pollutants.
