UPSC Prelims 2002 Q146: Geography – Atmosphere & Climatology
Assertion (A): 60° - 65° latitudes in both the hemispheres have a low - pressure belt instead of
high pressure.
Reason (R): The low - pressure areas are permanent over oceans rather than on land.
- (a) Both A and R are individually true and R is the correct explanation of A
- (b) Both A and R are individually true but R is not a correct explanation of A
- (c) A is true but R is false
- (d) A is false but R is true
Answer: (c) A is true but R is false
Explanation
Assertion-Reason: the low-pressure belt at 60-65° latitudes
| Statement | Verdict |
|---|---|
| Assertion: 60°-65° latitudes in both hemispheres have a low-pressure belt | True — the subpolar low belts |
| Reason: the low-pressure areas are permanent over oceans rather than on land | False as an explanation — the belt is a dynamic feature of the global circulation, not a matter of ocean versus land |
| Cause of the belt | Rising of air where warm westerlies meet cold polar easterlies, with the Earth's rotation |
| Result | A is true but R is false |
The subpolar lows lie near 60-65° in both hemispheres and arise from the convergence of westerlies and polar easterlies. The reason does not state the cause: the lows are not tied to the oceans by permanence, and the published key marks R as false.
Answer: (c) A is true but R is false.
Why each option is right or wrong
- (a) Incorrect. R is not accepted as true or as the explanation of A.
- (b) Incorrect. R is not accepted as true.
- (c) CORRECT. A is true; R is false as per the published key.
- (d) Incorrect. A is true, since the subpolar low belts exist.
Key point
Pressure belts: equatorial low, subtropical highs (30°), subpolar lows (60-65°), polar highs.
Remember
Subpolar lows form where westerlies meet polar easterlies.
Common mistakes
- Choosing R explains A because oceans do show strong lows.
- Treating the subpolar low as a thermal feature.
- Doubting that the assertion is true.
Exam tip
The subpolar low is dynamic and caused by convergence, not by oceans.
Sources
- NCERT Class XI Geography — Fundamentals of Physical Geography — Atmospheric Circulation and Weather Systems
- Savindra Singh — Climatology (Prayag Pustak Bhawan)