Important Geographical Lines – Equator, Tropics & Meridian
World Geography – Exam Preparation
Introduction: The Earth’s Invisible Grid
To locate any place on Earth accurately, geographers use imaginary lines drawn on the globe—called geographical lines.
These lines divide the Earth into latitudes and longitudes, helping determine location, time, and climate zones.
Memory Trick: "Lati = Flat (horizontal), Long = Long (vertical)"
The Equator – The Great Circle
| Feature | Description |
|---|---|
| Latitude | 0° |
| Length | ~40,075 km (largest circle on Earth) |
| Passes Through | South America, Africa, Asia |
| Climate Zone | Hottest region (Tropical) |
| Sun Position | Direct overhead twice a year (21 March & 23 September – Equinoxes) |
"0° = Zero Cold! → Hottest region."
Countries on the Equator: Ecuador, Colombia, Brazil, Gabon, Congo, Uganda, Kenya, Indonesia.
Tropic of Cancer & Tropic of Capricorn
Tropic of Cancer (23½° N)
- Passes through India, Saudi Arabia, Mexico, Egypt, China.
- Marks northernmost limit of Sun’s direct rays.
- Sun overhead on June 21 (Summer Solstice).
Tropic of Capricorn (23½° S)
- Passes through Brazil, Namibia, Australia, Chile, South Africa.
- Marks southernmost limit of Sun’s direct rays.
- Sun overhead on December 22 (Winter Solstice).
"Cancer North – Capricorn South → Alphabetical order (C before S)."
Arctic Circle & Antarctic Circle
| Line | Latitude | Location | Special Feature |
|---|---|---|---|
| Arctic Circle | 66½° N | Near North Pole | 24-hour day/night (June/Dec) |
| Antarctic Circle | 66½° S | Near South Pole | 24-hour day/night (Dec/June) |
"Arctic = North Lights, Antarctic = South Ice."
Prime Meridian (0° Longitude)
| Feature | Detail |
|---|---|
| Longitude | 0° |
| Passes Through | Greenwich (UK) |
| Use | Base for time calculation |
| Related Line | 180° → International Date Line |
"Prime means first – all time starts here!"
International Date Line (IDL – 180°)
- Opposite to the Prime Meridian.
- Separates two consecutive calendar days.
- Cross West → East: Subtract a day
- Cross East → West: Add a day
- Zigzag shape (avoids splitting islands)
"180° – where today meets tomorrow!"
Diagram – Important Geographical Lines
🌍 Earth’s Major Lines
90°N - North Pole
|
66½°N - Arctic Circle
|
23½°N - Tropic of Cancer
|
0° - Equator
|
23½°S - Tropic of Capricorn
|
66½°S - Antarctic Circle
|
90°S - South Pole
Order trick: "A Cat Took Every Cold Apple" (Arctic, Cancer, Equator, Capricorn, Antarctic)
Relationship Between Latitudes, Climate & Sunlight
| Latitude Zone | Extent | Climate Zone | Sunlight |
|---|---|---|---|
| Torrid Zone | 23½°N to 23½°S | Hot / Tropical | Direct rays |
| Temperate Zone | 23½°–66½° (N & S) | Moderate | Slanting rays |
| Frigid Zone | 66½°–90° (N & S) | Cold / Polar | Very slanting |
"Torrid = Toasty, Temperate = Tolerable, Frigid = Freezing."
Practice Questions (Delhi Police PYQ-style)
1
The Equator divides the Earth into —
Options: A) East and West B) North and South C) Land and Water D) Day and Night
Category: Core Geography
Show Answer
B) North and South
Quick Comparison Table
| Line | Degree | Divides Earth Into | Special Feature |
|---|---|---|---|
| Equator | 0° | North & South Hemispheres | Longest latitude; great circle |
| Tropic of Cancer | 23½° N | — | Sun vertical on June 21 |
| Tropic of Capricorn | 23½° S | — | Sun vertical on Dec 22 |
| Arctic Circle | 66½° N | — | Polar day/night zone |
| Antarctic Circle | 66½° S | — | Polar day/night zone |
| Prime Meridian | 0° | East & West Hemispheres | Basis for world time |
| International Date Line | 180° | — | Time & date change line |
"Every Clever Cat Acts Perfect Instantly." (Equator, Cancer, Capricorn, Arctic, Prime, International)
Exam Tricks & Mnemonics
Latitude Order Trick: Arctic → Cancer → Equator → Capricorn → Antarctic (A.C.E.C.A.)
Sun Position Dates:
- March 21: Equator (Spring Equinox)
- June 21: Tropic of Cancer (Summer Solstice)
- Sept 23: Equator (Autumn Equinox)
- Dec 22: Tropic of Capricorn (Winter Solstice)
Time Rule: 4 minutes per 1° longitude difference.
Revision & Exam Points
Most Repeated Questions: Equator divides hemispheres, Tropic degrees, Prime Meridian (Greenwich), IDL (180°), arctic/antarctic latitude.
Quick Recall: Equator = 0°, Cancer = 23½°N, Capricorn = 23½°S, Arctic = 66½°N, Antarctic = 66½°S, Prime = 0° (Long), IDL = 180°
Final Exam Tips
“These invisible lines silently shape our maps, our time, and even our seasons.”
Developed By Jan Mohammad
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