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Revision Notes

International Date Line

Maharashtra Board · Class 9 · Geography

Quick revision notes for International Date Line — Maharashtra Board Class 9 Geography. Key concepts, formulas, and definitions for last-minute revision.

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 Notes

Key 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?
International Date Line covers several key topics that are frequently asked in Maharashtra Board Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in International Date Line — Maharashtra Board Class 9 Geography?
Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision 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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