On 21st June, the Sun
- (a) does not set below the horizon at the Arctic Circle ✓ UPSC's answer
- (b) does not set below the horizon at Antarctic Circle
- (c) shines vertically overhead at noon on the Equator
- (d) shines vertically overhead at the Tropic of Capricorn
Why the answer is (a)
• On 21 June (summer solstice) the Sun is overhead at noon on the Tropic of Cancer (23.5° N), and the northern hemisphere has its longest day.
• The Arctic Circle (66.5° N) experiences 24 hours of daylight — the Sun does not set — option (a).
• The Antarctic Circle (b) has 24 hours of darkness that day; the Sun is not overhead at the Equator (c) (that happens at the equinoxes) or at the Tropic of Capricorn (d) (22 December).
• Hence option (a).
Why the other options are wrong
- (b) does not set below the horizon at Antarctic Circle
- The Antarctic Circle has 24-hour night on 21 June.
- (c) shines vertically overhead at noon on the Equator
- The Sun is overhead at the Equator only at the equinoxes.
- (d) shines vertically overhead at the Tropic of Capricorn
- The Sun is overhead at the Tropic of Capricorn on 22 December.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2019, held on 2 June 2019. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.