📌 Topic 02 of 6 · Chapter 11 · World Physical Geography
Latitude, Longitude & Time Zones
Important latitudes, IST, International Date Line, GMT — complete notes for UPSC & PSC exams.
🌐 Important Latitudes
| Line | Degree | Significance |
|---|---|---|
| Equator | 0° | Divides Earth into N & S hemispheres; longest circle; equal day & night throughout year |
| Tropic of Cancer | 23.5°N | Northernmost point of Sun’s overhead position (June 21); passes through 8 Indian states |
| Tropic of Capricorn | 23.5°S | Southernmost point of Sun’s overhead position (Dec 22) |
| Arctic Circle | 66.5°N | Midnight Sun; polar day/night; 6 months day, 6 months night at poles |
| Antarctic Circle | 66.5°S | Surrounds Antarctica; similar polar phenomena |
🌐 Important Longitudes
| Line | Degree | Significance |
|---|---|---|
| Prime Meridian (Greenwich) | 0° | Passes through Greenwich, UK; basis of GMT (Greenwich Mean Time) |
| International Date Line (IDL) | 180° | Opposite of Prime Meridian; date changes when crossed; zigzags to avoid dividing countries |
| India Standard Time (IST) | 82.5°E | Passes through Mirzapur (UP); IST = GMT + 5:30 hours |
⭐ Tropic of Cancer passes through India:
Gujarat → Rajasthan → MP → Chhattisgarh → Jharkhand → West Bengal → Tripura → Mizoram (8 states)
Memory: Good Road Makes Cars Jump Well Today Morning
Gujarat → Rajasthan → MP → Chhattisgarh → Jharkhand → West Bengal → Tripura → Mizoram (8 states)
Memory: Good Road Makes Cars Jump Well Today Morning
📌 IST Calculation:
82.5°E × 4 minutes/degree = 330 minutes = 5 hours 30 minutes ahead of GMT
India has a single time zone despite spanning ~29° of longitude (east-west)
Sun rises ~2 hours earlier in Arunachal Pradesh than in Gujarat
82.5°E × 4 minutes/degree = 330 minutes = 5 hours 30 minutes ahead of GMT
India has a single time zone despite spanning ~29° of longitude (east-west)
Sun rises ~2 hours earlier in Arunachal Pradesh than in Gujarat