UPSC Prelims 2022 Q29: Geography – Astronomy & Earth - Sun System
In the northern hemisphere, the longest day of the year normally occurs in the :
- (a) First half of the month of June
- (b) Second half of the month of June
- (c) First half of the month of July
- (d) Second half of the month of July
Answer: (b) Second half of the month of June
Explanation
The longest day in the Northern Hemisphere — summer solstice
| Event | Date | What happens |
|---|---|---|
| Summer solstice | About 21 June | Sun overhead at the Tropic of Cancer (23.5°N); longest day in the north |
| Winter solstice | About 22 December | Sun overhead at the Tropic of Capricorn; shortest day in the north |
| Equinoxes | About 21 March and 23 September | Sun over the Equator; day and night nearly equal |
Since the solstice falls on 20–21 June, the longest day is in the second half of June.
Why it happens:
| Cause | Effect |
|---|---|
| Earth's axis tilted 23.5° | The Northern Hemisphere leans towards the Sun in June |
| Revolution around the Sun | The overhead Sun shifts between the Tropics through the year |
Answer: (b) Second half of the month of June.
Why each option is right or wrong
- (a) Incorrect. The solstice falls on 20–21 June, which is in the second half of June.
- (b) CORRECT. The summer solstice (about 21 June) gives the longest day in the Northern Hemisphere.
- (c) Incorrect. Days are already getting shorter in early July.
- (d) Incorrect. By late July, days are noticeably shorter than at the solstice.
Key point
Summer solstice ≈ 21 June: Sun over the Tropic of Cancer; longest day in the Northern Hemisphere.
Remember
The longest day in the Northern Hemisphere is around 21 June.
Common mistakes
- Choosing the first half of June because summer is hot then.
- Thinking the hottest day and the longest day are the same; peak heat comes later.
- Mixing up the June and December solstices for the two hemispheres.
Exam tip
21 June = longest day north; 22 December = longest day south.
Sources
- NCERT Class VI — The Earth: Our Habitat, Ch 3 (Motions of the Earth)
- NCERT Class XI — Fundamentals of Physical Geography (The Earth in the Solar System)