Which one of the following statements is NOT correct?
- A.Biomass is a renewable source of energy
- B.Gobar gas is produced when cow-dung, crop residues, vegetable waste and sewage are allowed to decompose in the absence of oxygen
- C.Biogas generation reduces soil and water pollution
- D.Heating capacity of biogas is very low
Correct answer
Explanation
The correct answer is D, Heating capacity of biogas is very low. This statement is false: biogas is an excellent fuel with a high heating capacity.
Biogas is mostly methane, about 50 to 75 percent, with carbon dioxide and small amounts of other gases. Methane burns with a clean blue flame and no smoke, giving a good amount of heat, so biogas is widely used for cooking and lighting in villages. It is made in a biogas plant where cattle dung and other organic waste are broken down by anaerobic bacteria, and the slurry left behind is a rich manure.
A is correct because biomass such as wood, crop waste and dung can be replaced again and again. B is correct because gobar gas forms by anaerobic decomposition, that is without oxygen. C is correct because digesting waste in a closed plant keeps it from polluting soil and water and also yields manure.
Exam tip: biogas is mainly methane, made by anaerobic digestion; it burns smokeless with high heat.
Practice Questions
View allWhich one of the following biosphere reserves comprises islands with estuaries, beaches, coral reefs, salt marshes and mangroves ?
- A.Sunderban biosphere reserve
- B.Gulf of Mannar biosphere reserve
- C.Nilgiri biosphere reserve
- D.Nandadevi biosphere reserve
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Lying between India and Sri Lanka off Tamil Nadu, it is built around a chain of 21 small islands with estuaries, beaches, coral reefs, salt marshes, seagrass beds and mangroves.
Read the full explanation →Which of the following Ramsar Wetland sites is not situated in any of the Union Territories of India ?
- A.Hokera Wetland
- B.Point Calimere Wildlife and Bird Sanctuary
- C.Tsomoriri Lake
- D.Wular Lake
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Point Calimere, also called Kodiakkarai, lies in the Nagapattinam district of Tamil Nadu, a state, where the Coromandel Coast turns west towards Palk Strait.
Read the full explanation →In which one of the following groups of States in India is the Integrated Coastal Zone Management (ICZM) Project being implemented as a pilot investment?
- A.Gujarat, Kerala and Goa
- B.Kerala, Karnataka and Andhra Pradesh
- C.Gujarat, Odisha and West Bengal
- D.Maharashtra, Andhra Pradesh and Tamil Nadu
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The India Integrated Coastal Zone Management Project was launched by the Ministry of Environment and Forests in 2010 with World Bank support.
Read the full explanation →Which one of the following is a major environmental issue in eastern Canada ?
- A.Acid precipitation
- B.Groundwater depletion
- C.Land degradation
- D.Desertification
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Sulphur and nitrogen oxides from industries in the Great Lakes region and the US Midwest are carried by westerly winds and fall as acid rain and snow over eastern Canada.
Read the full explanation →Statement I : Global warming signifies the rise in global surface temperature. Statement II : The increase of concentration of greenhouse gases in the atmosphere causes the rise in global surface temperature.
- A.Both the statements are individually true and Statement II is the correct explanation of Statement I
- B.Both the statements are individually true but Statement II is not the correct explanation of Statement I
- C.Statement I is true but Statement II is false
- D.Statement I is false but Statement II is true
Show answer
Global warming is the long-term rise in the average temperature at the earth's surface, and it is driven mainly by the growing amount of greenhouse gases in the air, so Statement II explains Statement I. Sunlight warms the ground, which gives off heat as infrared radiation.
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