MCQ on Ozone layer Depletion with Answers for NEET

Solved MCQ on Ozone Layer Depletion Pdf

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Important Points to Remember about Ozone Depletion  : 

  1. Ozone layer depletion means the thinning of the ozone layer present in the upper atmosphere. That is harmful to nature and the atmosphere. Ozone layer depletion is one of the major problems for the atmosphere and also for all the living beings including the flora and fauna of this earth.
  2. The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere.
  3. The main effect of ozone depletion is an increase in UV-B rays reaching the earth's surface. It damages the human health such as increases in certain types of skin cancers, eye cataracts and immune deficiency disorders. UV rays also affect plant growth, reducing agricultural productivity.
  4. The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants, and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons).
  5. Human emissions of chlorine- and bromine-containing gases have increased substantially since the middle of the 20th century. The result has been global ozone depletion with the greatest losses occurring in polar regions.
  6. The ozone layer has been found to be depleted by certain natural processes such as sun-spots and stratospheric winds. But it does not cause more than 1-2% of the ozone layer depletion.
  7. By Minimizing the consumption of gases dangerous to the ozone layer, due to their content or manufacturing process, Minimizing the use of cars and avoid the use of cleaning products that are harmful to the environment and to us we can overcome these problems.


Multiple Choice Questions on Ozone Layer Depletion with Answers Pdf  : 

1. Ozone is___________

(a) A compound of oxygen 

(b) An allotropic oxygen

(c) An isotope of oxygen

(d) An isobar of oxygen

Answer: B


2. Which of the following is not the consequence of ozone layer depletion?

(a) Increased ultraviolet rays

(b) Malignant melanoma-Another form of skin cancer

(c) Cyanobacteria are sensitive to UV radiation and would be affected by its increase.

(d) None of these

Answer: D


3. Who discovered the ozone layer?

(a) Henri Buisson & Charles Fabry

(b) Carl Sagan & Charles Fabry

(c) G.M.B Dobson

(d) Carl Sagan & G.M.B Dobson

Answer: A


4. Ozone layer is present in___________

(a) Troposphere

(b) Mesosphere

(c) Thermosphere

(d) Stratosphere

Answer: D


4. Ozone depletion would magnify production of________

(a) Vitamin A.

(b) Vitamin B.

(c) Vitamin C.

(d) Vitamin D.

Answer: D


6. When was the first ozone hole discovered?

(a) 1980s

(b) 1950s

(c) 1970s

(d) 1990s

Answer: C


7. In which place the first ozone hole was discovered?

(a) Australia

(b) Antarctic

(c) Africa

(d) Arctic

Answer: B


8. Montreal Protocol was signed in_________

(a) 1986

(b) 1987

(c) 1988

(d) 1989

Answer: B


9. Result of ozone hole is__________

(a) greenhouse effect

(b) global warming

(c) acid rain

(d) UV rays reach the earth

Answer: D


10. Who discovered the formation of ozone from photochemical reactions?

(a) G.M.B Dobson

(b) Sydney Chapman

(c) Carl Sagan

(d) Henri Buisson

Answer: A


11. “International Day for the Preservation of the Ozone Layer” or “World Ozone Day” is celebrated on_________

(a) September 16

(b) September 18

(c) October 16

(d) October 18

Answer: A


12. What is the average concentration of ozone in the ozone layer of the atmosphere?

(a) Nearly 100%

(b) Greater than 90%

(c) Less than 10ppm

(d) Between 10-50%

Answer: C


13. Biological importance of ozone layer is_____________

(a) Ozone layer stops ultraviolet rays

(b) Ozone layer reduces greenhouse effect

(c) Ozone layer reflects radio waves

(d) Ozone layer controls O2 / H2O radio in the atmosphere.

Answer: A


14. In which sphere Ozone layer depletion is found?

(a) Ionosphere

(b) Stratosphere

(c) Lithosphere

(d) None of these

Answer: B


15. In the breakdown of the ozone layer, the ozone (O3) reacts directly with__________

(a) Ultraviolet light

(b) Chlorine atoms

(c) Oxygen atoms

(d) CFC molecules

Answer: B


16. The depletion in the Ozone layer is caused by______

(a) Carbon dioxide

(b) Nitrous oxide

(c) Methane

(d) Chlorofluorocarbon

Answer: D


17. Montreal protocol is related to the_________

(a) Global warming

(b) Ozone layer depletion

(c) Sustainable development

(d) Food security

Answer: B


18. CFCs (chlorofluorocarbons) are greenhouse gases that have caused a rise of 3 degree C in the global temperatures in the past century. Name the CFC that is used in refrigerators.

(a) Carbon dioxide

(b) Methane

(c) Ammonia

(d) Freon

Answer: D


19. Which gas is responsible for the depletion of the ozone layer?

(a) Carbon dioxide

(b) Methane

(c) Chlorofluorocarbon

(d) Sulfur dioxide

Answer: C


20. Which of the following devices can be used to measure ozone in the stratosphere from the ground?

(a) Spectrometer

(b) Photometer

(c) Spectrophotometer

(d) Spectro-ozonometer

Answer: C


21. Main cause of ozone holes and its depletion is________

(a) propellants

(b) foam-blowing agents

(c) halocarbon refrigerants

(d) all of these

Answer: D


22. Ozone can be destroyed by the following free radical (s) __________

(a) Chlorine radical (Cl)

(b) hydroxyl radicals (OH)

(c) nitric oxide radical (NO)

(d) all of these

Answer: D


23. How does the ozone molecule form?

(a) Ozone (O3) is a molecule formed by two atoms of oxygen.

(b) Ozone (O3) is a molecule formed by three atoms of oxygen.

(c) Ozone (O3) is a molecule formed by four atoms of oxygen.

(d) None of these.

Answer: B


24. Ozone-layer is getting depleted because of__________

(a) Excessive use of automobiles

(b) Excessive formation of industrial units

(c) Excessive use of man-made compounds containing both fluorine and chlorine

(d) Excessive deforestation

Answer: C


25. Which of the following statements about ozone is true?

(a) Ozone is a major constituent of photochemical smog

(b) Ozone is highly reactive

(c) It protects us from harmful UV radiations of sun

(d) All of the above

Answer: C


26. Assertion: An equilibrium is established between generation and destruction of ozone, leading to a steady state concentration of ozone layer in the stratosphere at an altitude of 20-30 km above sea level.

Reason: The thickness of the ozone layer is generally larger above the equator and smaller above the poles.

(a) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

(b) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

(c) Assertion is correct but Reason is incorrect

(d) Both Assertion and Reason are incorrect

Answer: B


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