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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?
Understand the core concepts first, then work through the 45 practice questions available for this chapter. Revise formulas and 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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