Question 41 from UPSC CSE 2019 - Geography

Question

On 21st June, the Sun

Accepted Answer

Correct Option: A. does not set below the horizon at the Arctic Circle

Strategy: The phrase 'on 21st June' should immediately trigger recall of the Summer Solstice when the Sun is over the Tropic of Cancer. The Arctic Circle is specifically associated with the phenomenon of the Midnight Sun where the Sun does not set during this time. Options referencing the Equator or Tropic of Capricorn on June 21st are out of scope for this date, allowing quick elimination.

Key Info: June 21st marks the Summer Solstice in the Northern Hemisphere, when the Earth's axial tilt is most inclined towards the Sun.

- On this day, the Sun is directly overhead at noon at the Tropic of Cancer (23.5°N).
- At the Arctic Circle (66.5°N), the Sun remains above the horizon for a full 24 hours, causing the 'Midnight Sun' phenomenon. This period of continuous daylight lasts longer as one moves closer to the North Pole, culminating in about six months of daylight at the Pole itself.
- The Antarctic Circle (66.5°S) simultaneously experiences polar night, with the Sun not rising above the horizon.
- On June 21st, the Equator does not experience the Sun at zenith; this occurs during the equinoxes (around March 21st and September 23rd).
- The Tropic of Capricorn is the sub-solar point only during the December Solstice (around December 22nd).

This solstice marks the longest day and shortest night for locations in the Northern Hemisphere. The event has significant climatic, ecological, and cultural implications, reflected in traditions and festivals across northern cultures.

Answer

Option B: does not set below the horizon at the Antarctic Circle

Answer

Option C: shines vertically overhead at noon on the Equator

Answer

Option D: shines vertically overhead at the Tropic of Capricorn