Assertion (A) : In urban areas, smog episodes occur frequently in winters.…
2017
Assertion (A) : In urban areas, smog episodes occur frequently in winters.
Reason (R) : In winters, a lot of biomass is burnt by people for heating purposes or to keep themselves warm.
Choose the correct answer from the code given below :
Answer: B. Both (A) and (R) are true but (R) is not the correct explanation of (A) — CONCEPTWinter smog becomes severe when pollutants accumulate near the ground. A temperature inversion and weak winds reduce vertical mixing; emissions supply…
- A.
Both (A) and (R) are true and (R) is the correct explanation of (A)
- B.
Both (A) and (R) are true but (R) is not the correct explanation of (A)
- C.
(A) is true and (R) is false
- D.
Both (A) and (R) are false
Show answer & explanation
Correct answer: B
CONCEPT
Winter smog becomes severe when pollutants accumulate near the ground. A temperature inversion and weak winds reduce vertical mixing; emissions supply particles and gases, while weather conditions control their dispersion.
In an assertion-reason item, first determine the truth of each statement independently, and then test whether the reason fully explains the assertion.
APPLICATION
Assertion (A) is true: urban smog episodes commonly intensify in winter because stable air, weak mixing, and temperature inversions trap pollutants. Reason (R) is also true: winter heating can involve substantial biomass burning and adds smoke and particles. However, that activity is one emission source; it does not by itself explain the general seasonal occurrence of urban winter smog, whose immediate atmospheric mechanism is poor dispersion and inversion-driven trapping.
CONTRAST
“Both (A) and (R) are true and (R) is the correct explanation of (A)” treats a contributing emission source as the complete explanation.
“Both (A) and (R) are true but (R) is not the correct explanation of (A)” separates the truth of the two statements from the adequacy of their causal link.
“(A) is true and (R) is false” overlooks winter biomass burning used for heating.
“Both (A) and (R) are false” conflicts with both observed winter smog episodes and seasonal biomass-burning emissions.
CROSS-CHECK
The official final key for UGC NET November 2017 Paper I, question 42, identifies the response “Both (A) and (R) are true, but (R) is not the correct explanation of (A).”
RESULT
Both (A) and (R) are true, but (R) is not the correct explanation of (A).