UPSC Prelims 2019 Q20: Geography – Physical Geography
- (a) does not set below the horizon at the Arctic Circle
- (b) does not set below the horizon at the Antarctic Circle
- (c) shines vertically overhead at noon on the Equator
- (d) shines vertically overhead at the Tropic of Capricorn
Answer: (a) does not set below the horizon at the Arctic Circle
Explanation
21st June: Summer Solstice in Northern Hemisphere
| Option | Claim | Verdict | Detail |
|---|---|---|---|
| (a) | Sun does NOT set at Arctic Circle on 21 June | TRUE | On 21 June (Northern Summer Solstice), sun is vertically overhead at Tropic of Cancer. At Arctic Circle (66.5 N) and northward, sun does NOT set - midnight sun phenomenon. |
| (b) | Sun does not set at Antarctic Circle on 21 June | FALSE | On 21 June, Antarctic Circle has polar night - sun does NOT rise (opposite phenomenon). |
| (c) | Sun shines vertically over Equator on 21 June | FALSE | Sun is vertical over Equator only on Equinoxes (March 21, Sept 23), not June solstice. |
| (d) | Sun shines vertically over Tropic of Capricorn on 21 June | FALSE | Sun is vertical over Tropic of Capricorn on December 22 (Winter Solstice for N. Hemisphere), not June. |
Answer: (a) does not set below the horizon at the Arctic Circle.
Why each option is right or wrong
- (a) CORRECT. On 21 June (Northern Summer Solstice), the sun does not set at the Arctic Circle - midnight sun.
- (b) Incorrect. Antarctic Circle experiences polar night (sun does not rise) on 21 June.
- (c) Incorrect. Sun is overhead at Equator on Equinoxes (March 21, Sept 23), not June solstice.
- (d) Incorrect. Sun is overhead at Tropic of Capricorn on December 22 (winter solstice).
Key point
21 June = N-Solstice: Sun overhead at Tropic of Cancer; Arctic Circle has midnight sun (no sunset); Antarctic Circle has polar night.
Remember
On 21st June (Northern Summer Solstice), the sun is vertically overhead at the Tropic of Cancer. At the Arctic Circle and beyond, the sun does not set below the horizon - the 'midnight sun' phenomenon. The Antarctic Circle experiences the opposite - polar night.
Common mistakes
- Reversing solstice hemispheres - Northern Summer Solstice = Southern Winter Solstice.
- Assuming sun is overhead at Equator on solstices - it is on equinoxes.
- Confusing 'not setting' at Arctic Circle (June) with 'not rising' (December).
Exam tip
Solstice/Equinox anchor: March 21 (Vernal Equinox) - sun over Equator. June 21 (N-Solstice) - sun over Tropic of Cancer, midnight sun in Arctic. Sept 23 (Autumn Equinox) - sun over Equator. Dec 22 (N-Winter Solstice) - sun over Tropic of Capricorn, midnight sun in Antarctic.
Sources
- NCERT Class 11 - Fundamentals of Physical Geography (Earth's Motion and Solstices)
- NCERT Class 6 - The Earth in the Solar System