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Revision Notes
International Date Line — Revision Notes
Maharashtra Board · Class 9 · Geography
International Date Line revision notes for Maharashtra Board Class 9 Geography: 4 topics in quick points. Includes Understanding Time and Earth's.
45 questions20 flashcards4 concepts
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Key Topics to Revise
1
Understanding Time and Earth's Rotation
- Earth rotates 360° in 24 hours, which means 15° per hour (360÷24=15)
- Earth rotates from west to east, so eastern regions experience sunrise first
- Prime Meridian (0°) at Greenwich, England determines GMT/UTC
2
Concept and Location of International Date Line
- IDL is located approximately along 180° meridian in the Pacific Ocean
- Established in 1884 under American Professor Davidson's leadership
- Not a straight line - deviates east and west to avoid land masses
3
Rules for Crossing the International Date Line
- When traveling WEST to EAST across IDL: SUBTRACT one day
- When traveling EAST to WEST across IDL: ADD one day
- The day officially starts west of IDL and ends east of IDL
4
Practical Applications and Examples
- Airlines use IDL for flight scheduling and ticketing
- New Year celebrations start west of IDL (Pacific islands) and end east of IDL (Americas)
- International shipping and cargo tracking depend on IDL
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Full NotesKey Concepts
Earth rotates 360° in 24 hoursThe 180° meridian is the theoreticalWhen traveling westward across the IDLThe IDL was established in 1884
Frequently Asked Questions
What are the important topics in International Date Line for Maharashtra Board Class 9 Geography?
Key topics in International Date Line include Understanding Time and Earth's Rotation, Concept and Location of International Date Line, Rules for Crossing the International Date Line, Practical Applications and Examples. Study these first, then practise questions on each for Class 9 exams.
How should I revise International Date Line for Class 9 exams?
Learn the core ideas first, then work through the 45 practice questions on International Date Line. Revise definitions regularly and use flashcards for quick recall before the exam.
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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