Class 9 MAHARASHTRA STATE TEXTBOOK BUREAU Solutions Social Studies Chapter 7 - International Date Line
International Date Line Exercise 62
Solution 1(A)
Solution 2(1)
a. East to West
Solution 2(2)
b. Wednesday 9 p.m.
Solution 2(3)
d. 1800
Solution 2(4)
a. East
Solution 2(5)
c. Transportation schedules
Solution 3(1)
- The IDL has helped in coordinating between international airlines, transportation services, economic and trade activities.
- With the help of IDL, it has become easier to keep an accurate track of all calculations related to time especially when it comes to travelling from Eastern to Western Hemisphere and vice versa.
- It is only because of the IDL that the schedules of the traffic worldwide are organised properly.
Solution 3(2)
The IDL passes through the Pacific Ocean. With reference to the IDL the day on earth starts in the west and ends in the East. It is one and the same day only at 12 o'clock midnight at the 180° meridian. For the countries lying to the east of it i.e. the USA, Chile, etc. it is the end of the day while for the countries lying to the west of it i.e. Japan, Australia, etc. it is the start of a new day. Thus, a new day starts in Pacific Ocean on Earth.
Solution 4(1)
Following points were taken into consideration while drawing the International Date Line. 1. The direction of travel: The direction of travel - The sun travels from east to west and the earth rotates from west to east. Thus, the countries in the west, 12.00 at midnight is the end of the day and the countries of the east, it is the start of the day. 2. The current day and date: When we travel across the meridian, the day and the date changes. While travelling from east to west, one day has to add to the day of commencing the journey. But while travelling from west to east, the same day is considered upon arrival.
Solution 4(2)
The International Date Line runs down the middle of the Pacific Ocean. If we cross the dateline moving east, we will subtract a day, whereas if we are moving west we will add a day. For example, if today is Saturday and we crossed the International Dateline from west to east then it would be Friday. If we went east to west it would be Sunday.
Solution 4(3)
The IDL is not a straight line. It is goes zig-zag at some places. It is zigzagged to avoid splitting one country into two days. If it would have been a straight line then, one part of the country would have one date and the other part would have a different date.
Solution 4(4)
An effort has been made to make the IDL pass through the Pacific Ocean completely. If it would have passed through land, then the people living in western and eastern parts of the same country would have had to follow different dates and timings. It is to avoid such confusion, that the IDL does not pass through the land.
Solution 4(5)
According to the international conventions, the start of a date is considered to be at 180° meridian. This is because, when one crosses the 180° meridian from east or west, there is a difference of 12 hours from prime meridian. Accordingly, an adjustment or change during a day is made at 180° meridian. Due to these reasons, the IDL is considered with respect to the 180° meridian only.
Solution 5(1)
IDL will be crossed. Students need to show this on the map themselves.
Solution 5(2)
IDL will not be crossed
Solution 5(3)
IDL will be crossed
Solution 5(4)
IDL will be crossed.
Solution 5(5)
IDL will not be crossed.
