Consider the following statements : 1. Jet streams occur in the Northern Hemisphere only. 2. Only some cyclones develop an eye. 3. The temperature inside the eye of a cyclone is nearly 10°C lesser than that of the surroundings. Which of the statements given above is/are correct ?
- (a) 1 only
- (b) 2 and 3 only
- (c) 2 only ✓ UPSC's answer
- (d) 1 and 3 only
Why the answer is (c)
• Statement 2 is correct: only well-organised, intense tropical cyclones develop a clear eye; weaker storms and extra-tropical cyclones usually do not.
• Statement 1 is wrong: jet streams (polar and subtropical) exist in both hemispheres.
• Statement 3 is wrong: the eye is warmer than its surroundings, because subsiding air is compressed and heated; the temperature difference can be 10 °C or more, but in the warm direction.
• Hence 2 only, option (c).
Why the other options are wrong
- (a) 1 only
- Statement 1 is wrong: jet streams occur in both hemispheres.
- (b) 2 and 3 only
- Statement 3 is wrong: the eye is warmer, not cooler.
- (d) 1 and 3 only
- Statements 1 and 3 are wrong.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2020, held on 4 October 2020. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.