(i) What is the main component of the Earth's atmosphere?
(a) Oxygen
(b) Nitrogen
(c) Carbon Dioxide
(d) Argon
Ans: (b)
Nitrogen makes up 78% of the Earth's atmosphere.
(ii) What is the primary reason for a lighted candle covered with a glass tumbler going out?
(a) Lack of heat
(b) Lack of fuel
(c) Lack of oxygen
(d) Lack of wax
Ans: (c)
The candle goes out because it uses up all the oxygen inside the glass.
(iii) Which process converts atmospheric nitrogen into nitrates that plants can use?
(a) Respiration
(b) Combustion
(c) Nitrogen Fixation
(d) Photosynthesis
Ans: (c)
Nitrogen fixation is the process where bacteria convert atmospheric nitrogen into nitrates.
(iv) What role does the ozone layer play in the Earth's atmosphere?
(a) It absorbs harmful UV rays
(b) It produces oxygen
(c) It regulates temperature
(d) It creates wind energy
Ans: (a)
The ozone layer protects life by absorbing harmful UV rays from the sun.
(v) Which gas is released by animals during respiration?
(a) Oxygen
(b) Carbon Dioxide
(c) Nitrogen
(d) Argon
Ans: (b)
Animals release carbon dioxide during the process of respiration.
(i) Air contains _________ gases, including nitrogen, oxygen, carbon dioxide, and water vapor.
Ans: several
Air is a mixture of several gases.
(ii) Plants make oxygen through the process of ________________.
Ans: photosynthesis
Oxygen is produced by plants during the process of photosynthesis.
(iii) The layer of __________ gas in the upper atmosphere prevents harmful UV rays from entering the Earth's atmosphere.
Ans: ozone
The ozone layer protects against harmful UV rays.
(iv) Water vapor causes weather conditions such as ____________, ____________, and ____________.
Ans: rain, snowfall, dew
Water vapor leads to various weather conditions.
(v) Wind is a source of energy used in __________ to draw water, grind flour, and generate electricity.
Ans: windmills
Windmills use wind energy for various purposes.
Match the terms in Column A with their corresponding descriptions in Column B.
Ans:
(i) Clean air is visible and has a distinct smell.
Ans: False
Clean air is colorless and odorless.
(ii) The atmosphere extends up to about 100 km above the Earth's surface.
Ans: False
The atmosphere extends up to about 600 km above the Earth's surface.
(ii) Combustion is the process of burning, which involves using nitrogen.
Ans: False
Combustion involves using oxygen, not nitrogen.
(iii) Water vapor in the air can cause rain, but it does not play a role in forming clouds.
Ans: False
Water vapor condenses into water droplets, forming clouds.
(iv) All animals can use nitrogen directly from the air for their growth.
Ans: False
Animals cannot use nitrogen directly; it needs to be converted into nitrates first.
22 videos|80 docs|16 tests
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1. What is air and why is it important? |
2. How does air pollution affect our health? |
3. What are the major sources of air pollution? |
4. How can we reduce air pollution in our daily lives? |
5. What are the effects of air pollution on the environment? |
22 videos|80 docs|16 tests
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