Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Observed and projected decreases in ozone have generated worldwide concern.
Reason (R): Chlorofluorocarbons (CFCs) are used as aerosol propellants.
In the light of the above statements, choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Both (A) and (R) are true but (R) is not the correct explanation of (A).
Assertion (A): Observed and projected decreases in ozone have generated worldwide concern. — True. Falling ozone has caused worldwide concern.
Reason (R): Chlorofluorocarbons (CFCs) are used as aerosol propellants. — True. CFCs are used in air-conditioners, refrigerators and as aerosol propellants. They are a source of the compounds that deplete ozone.
Why R does not explain A?
R tells us where the harmful compounds come from. It does not say why a fall in ozone worries the world. The real reason is that the ozone layer prevents most harmful ultraviolet light from passing through the atmosphere. Less ozone means more UV radiation, which damages living organisms.
NCERT (2026-27): “Box 7.2: Ozone Depletion … The origins of these compounds are chlorofluorocarbons (CFC), used as cooling substances in air-conditioners and refrigerators, or as aerosol propellants, and bromofluorocarbons (halons), used in fire extinguishers. As a result of depletion of the ozone layer, more ultraviolet (UV) radiation comes to Earth and causes damage to living organisms. … Since the ozone layer prevents most harmful wavelengths of ultraviolet light from passing through the Earth’s atmosphere, observed and projected decreases in ozone have generated worldwide concern. …” |