250+ TOP MCQs on Greenhouse Gases – 2 and Answers

Environmental Science Multiple Choice Questions on “Greenhouse Gases – 2”.

1. The GWP depends on which of the following factors?
a) Absorption capability of IR radiations
b) Atmospheric life-time
c) Range of IR wavelengths it can absorb
d) All of the mentioned
Answer: d
Clarification: The global warming potential of a given gas depends on its absorption capability over range of IR wavelengths and how long it stays in the atmosphere.

2. Which of the following mentioned GHGs has the highest atmospheric lifetime?
a) Carbon tetrafluoride
b) Nitrous oxide
c) Methane
d) CFC
Answer: a
Clarification: Among the mentioned gases, carbon tetrafluoride has the largest life time of 50,000 years and a GWP of approximately 5000 over a period of 20 years.

3. Which of the following gases has the highest radiative efficiency?
a) Sulphur hexafluoride
b) Carbon tetrachloride
c) PFTBA
d) CFC
Answer: c
Clarification: Perfluorotributylamine used as in heat transfer and electrical industry has the highest radiative efficiency, i.e. it can effectively trap the long wave radiation better than other greenhouse gases.

4. Which of the following compounds have the highest GWP?
a) Nitrous oxide
b) CFC
c) Water vapour
d) Sulphur hexafluoride
Answer: d
Clarification: Sulphur hexafluoride has a potential of warming the planet 16,300 times greater than carbon dioxide.

5. Anthropogenic sources of carbon dioxide are 20 times greater than natural carbon dioxide sources.
a) True
b) False
Answer: b
Clarification: Natural sources of CO2 are twenty times greater than anthropogenic sources, but at the same time they are balanced out by various other natural processes.

6. What is the reason for extreme difference in temperatures at day and night in deserts?
a) Carbon dioxide concentrations are low in desert regions, therefore heat escapes easily
b) Sand has high heat conduction properties
c) Lack of moisture leads to escape of heat
d) All of the mentioned
Answer: c
Clarification: Lack of moisture, i.e. water vapour, prevents re-radiation of the IR rays from the surface, thereby not trapping heat. Hence desert has high temperatures during the day and extremely low temperatures in the night.

7. What does the method of “enhanced weathering” infer?
a) It is a method used to spray sulphate aerosols to reduce the greenhouse effect
b) It is a method of cloud seeding that is done to reduce the contribution of clouds to greenhouse effect
c) It is a method used to remove CO₂from the air
d) None of the mentioned
Answer: d
Clarification: Enhanced weathering is a form of geo-engineering where minerals are broken down to help remove CO2 from air.

8. What does the process of carbon sequestration mean?
a) Removal of CO₂ from the atmosphere
b) Storage of CO₂ by depositing in reservoir
c) Removal of CO₂ from the atmosphere & Storage of CO₂ by depositing in reservoir
d) None of the mentioned
Answer: c
Clarification: Carbon sequestration is the process of removal of CO₂ and storing them in carbon sinks to minimise their impact on global warming.

9. Which of the following is a sink for carbon?
a) Wetlands
b) Old oil fields
c) Saline waterbodies
d) All of the mentioned
Answer: d
Clarification: Wetlands, old oil fields, saline waterbodies, etc. are important carbon storages and help in removal of CO2 from atmosphere.

10. Which of the following greenhouse gas is contributed by cattle farming?
a) Nitrous oxide
b) Methane
c) Carbon monoxide
d) All of the mentioned
Answer: b
Clarification: Methane is a gas released by the digestive processes of cattle and hence cattle farming also contribute to greenhouse effect.

11. Volcanic eruptions contribute to the global greenhouse phenomenon.
a) True
b) False
Answer: b
Clarification: Volcanic eruptions release sulphate aerosols which help in blocking sun’s radiations from reaching the Earth’s surface. Hence they aid in generating a cooling effect.

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