Ozone Layer MCQs

  1. What is the ozone layer?
    A) A layer of carbon dioxide
    B) A layer rich in ozone gas (O₃)
    C) A layer of nitrogen gas
    D) A layer of hydrogen gas
    Answer: B) A layer rich in ozone gas (O₃)
  2. The ozone layer is mainly found in which part of the atmosphere?
    A) Troposphere
    B) Mesosphere
    C) Stratosphere
    D) Thermosphere
    Answer: C) Stratosphere
  3. What is the chemical formula of ozone?
    A) O₂
    B) CO₂
    C) O₃
    D) H₂O
    Answer: C) O₃
  4. The ozone layer protects Earth from:
    A) Infrared rays
    B) Ultraviolet rays
    C) Radio waves
    D) Sound waves
    Answer: B) Ultraviolet rays
  5. Which type of ultraviolet radiation is mostly absorbed by the ozone layer?
    A) UV-A
    B) UV-B
    C) UV-C
    D) Both UV-B and UV-C
    Answer: D) Both UV-B and UV-C
  6. Who discovered the ozone layer?
    A) Isaac Newton
    B) Charles Fabry and Henri Buisson
    C) Albert Einstein
    D) Galileo Galilei
    Answer: B) Charles Fabry and Henri Buisson
  7. Ozone is formed when:
    A) Oxygen molecules react with sunlight
    B) Nitrogen reacts with oxygen
    C) Carbon dioxide splits
    D) Water vapor condenses
    Answer: A) Oxygen molecules react with sunlight
  8. Which instrument is used to measure ozone concentration?
    A) Barometer
    B) Hygrometer
    C) Spectrophotometer
    D) Thermometer
    Answer: C) Spectrophotometer
  9. Ozone concentration is measured in:
    A) Joules
    B) Dobson Units
    C) Newtons
    D) Watts
    Answer: B) Dobson Units
  10. The largest ozone hole was first observed over:
    A) Asia
    B) Europe
    C) Antarctica
    D) Africa
    Answer: C) Antarctica
  11. Ozone depletion means:
    A) Increase in ozone concentration
    B) Reduction in ozone concentration
    C) Formation of clouds
    D) Increase in rainfall
    Answer: B) Reduction in ozone concentration
  12. Which chemicals are mainly responsible for ozone depletion?
    A) Sulfur dioxide
    B) Chlorofluorocarbons (CFCs)
    C) Oxygen
    D) Nitrogen
    Answer: B) Chlorofluorocarbons (CFCs)
  13. CFCs were commonly used in:
    A) Refrigerators and aerosols
    B) Cars only
    C) Ships only
    D) Power plants only
    Answer: A) Refrigerators and aerosols
  14. Which element released from CFCs destroys ozone?
    A) Sodium
    B) Potassium
    C) Chlorine
    D) Iron
    Answer: C) Chlorine
  15. Excessive UV radiation can cause:
    A) Skin cancer
    B) Blindness
    C) Cataracts
    D) All of these
    Answer: D) All of these
  16. The international agreement to protect the ozone layer is:
    A) Kyoto Protocol
    B) Paris Agreement
    C) Montreal Protocol
    D) Geneva Convention
    Answer: C) Montreal Protocol
  17. The Montreal Protocol was signed in:
    A) 1972
    B) 1987
    C) 1992
    D) 2000
    Answer: B) 1987
  18. Which country hosts the largest seasonal ozone hole?
    A) India
    B) Brazil
    C) Antarctica region
    D) China
    Answer: C) Antarctica region
  19. Ozone in the lower atmosphere is considered:
    A) Beneficial
    B) Harmless
    C) A pollutant
    D) A fertilizer
    Answer: C) A pollutant
  20. The ozone layer acts as Earth’s:
    A) Cooling system
    B) Protective shield
    C) Water source
    D) Energy source
    Answer: B) Protective shield
  21. Which radiation reaches Earth in greater amounts when ozone is depleted?
    A) Gamma rays
    B) X-rays
    C) UV-B rays
    D) Radio waves
    Answer: C) UV-B rays
  22. Ozone is continuously:
    A) Produced and destroyed naturally
    B) Produced only
    C) Destroyed only
    D) Frozen permanently
    Answer: A) Produced and destroyed naturally
  23. Which gas is essential for the formation of ozone?
    A) Carbon dioxide
    B) Oxygen
    C) Methane
    D) Hydrogen
    Answer: B) Oxygen
  24. The ozone layer is located approximately:
    A) 5–10 km above Earth
    B) 10–50 km above Earth
    C) 60–80 km above Earth
    D) 100–120 km above Earth
    Answer: B) 10–50 km above Earth
  25. Which organization monitors ozone depletion globally?
    A) FIFA
    B) WHO only
    C) WMO and UNEP
    D) OPEC
    Answer: C) WMO and UNEP
  26. Increased UV radiation can damage:
    A) Plants
    B) Marine life
    C) Human health
    D) All of these
    Answer: D) All of these
  27. Which of the following is an ozone-friendly alternative to CFCs?
    A) HCFCs and HFCs
    B) Carbon monoxide
    C) Sulfur dioxide
    D) Nitrogen oxide
    Answer: A) HCFCs and HFCs
  28. The ozone layer is sometimes called:
    A) Earth’s sunscreen
    B) Earth’s engine
    C) Earth’s magnet
    D) Earth’s core
    Answer: A) Earth’s sunscreen
  29. Recovery of the ozone layer is mainly due to:
    A) Increased rainfall
    B) Reduced use of CFCs
    C) Increased industrialization
    D) Deforestation
    Answer: B) Reduced use of CFCs
  30. Why is the ozone layer important?
    A) It produces oxygen
    B) It absorbs harmful UV radiation
    C) It causes rainfall
    D) It increases gravity
    Answer: B) It absorbs harmful UV radiation

Leave a Comment