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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
Mention the contribution of the following scientists :
- Antoine Lavoisier
- Robert Boyle
- Joseph Priestley
- Sir W. Ramsay
Fill in the blank:
_____________ discovered the oxygen gas.
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.
Tick (√) the correct alternative from the choice given for the following statement.
The gases which cause acid rain are
What is meant by the term ‘atmosphere’? State the role played by the atmosphere for the survival of mankind.
Name the following.
Inert gases in the air
Match the statements in List I with the correct answer from List II.
| List I | List II |
| 1. The constituent of air which is around 0.02% | A: Nitrogen |
| 2. The constituent of air which is inert or unreactive | B: Oxygen |
| 3. The constituent of air which is non-combustible, but supports combustion. |
C: Sulphur dioxide |
| 4. A pollutant in air responsible for acid rain | D: Carbon dioxide |
| 5. The main rare gas present in air. | E: Argon |
The process of conversion of iron into hydrated form of oxides is called _______.
In the boxes of Column, I the letters of some words got jumbled. Arrange them in proper form in the boxes given in Column II
| Column I | Column II | ||
| (a) | \[\boxed{\text{D}}\]\[\boxed{\text{I}}\]\[\boxed{\text{L}}\]\[\boxed{\text{L}}\]\[\boxed{\text{M}}\]\[\boxed{\text{W}}\]\[\boxed{\text{I}}\]\[\boxed{\text{N}}\] | (a) | `squaresquaresquaresquaresquaresquaresquare square` |
| (b) | \[\boxed{\text{Y}}\]\[\boxed{\text{N}}\]\[\boxed{\text{O}}\]\[\boxed{\text{G}}\]\[\boxed{\text{X}}\]\[\boxed{\text{E}}\] | (b) | `squaresquaresquaresquaresquare square` |
| (c) | \[\boxed{\text{M}}\]\[\boxed{\text{E}}\]\[\boxed{\text{S}}\]\[\boxed{\text{K}}\]\[\boxed{\text{O}}\] | (c) | `squaresquaresquaresquaresquare` |
| (d) | \[\boxed{\text{T}}\]\[\boxed{\text{U}}\]\[\boxed{\text{D}}\]\[\boxed{\text{S}}\] | (d) | `squaresquaresquare` |
