Given below are two statements: Statement I: Atmospheric stability is…
2022
Given below are two statements:
Statement I: Atmospheric stability is important because it determines the ability of pollutants to disperse vertically in the atmosphere.
Statement II: In summer season in India, the atmosphere is generally stable.
Choose the correct answer from the options given below:
Answer: C. Statement I is true but Statement II is false — Concept: Atmospheric stability describes how readily an air parcel continues to rise or sink after being displaced. Stable stratification suppresses vertical…
- A.
Both Statement I and Statement II are true
- B.
Both Statement I and Statement II are false
- C.
Statement I is true but Statement II is false
- D.
Statement I is false but Statement II is true
Attempted by 2 students.
Show answer & explanation
Correct answer: C
Concept: Atmospheric stability describes how readily an air parcel continues to rise or sink after being displaced. Stable stratification suppresses vertical motion, whereas unstable stratification promotes convection and mixing.
Because pollutant plumes move with the surrounding air, this stability state controls vertical dilution: stable air limits dispersion, while unstable air enhances it.
Application: Apply the stability–mixing relationship to each statement.
Statement I links atmospheric stability with the vertical dispersal of pollutants. That link follows directly from the effect of stability on buoyant vertical motion, so Statement I is true.
Statement II describes the Indian summer atmosphere as generally stable. Strong summer surface heating commonly creates rising warm air, convection, and turbulent mixing, which are signatures of instability; therefore Statement II is false.
Cross-check: Stable conditions are commonly associated with inversions and pollutant trapping near the surface, whereas heated daytime conditions deepen the mixed layer. This confirms the two assessments.
Contrast: The remaining combinations fail for these value-specific reasons.
“Both statements are true” conflicts with the convective mixing produced by strong summer heating.
“Both statements are false” overlooks the role of stability in controlling vertical pollutant dilution.
“Statement I is false but Statement II is true” reverses both the dispersion principle and the usual summer-heating effect.
Result: Statement I is true, but Statement II is false.