What will happen if you are flying east across the International Date Line?
- (a)You will lose 12 hours
- (b)You will gain 12 hours
- (c)You will gain 24 hours
- (d)You will lose 24 hours
Correct — D, You will lose 24 hours. The land on the eastern side of the International Date Line keeps a date one full day earlier than the land on its western side. So a traveller flying eastward crosses from the later side to the earlier side and must set the calendar back by one whole day — a subtraction of 24 hours, which is what the paper means by losing 24 hours. Whichever way you cross, the adjustment is always a complete day.
- (a)You will lose 12 hours — The Date Line adjustment is never a half-day. The figure 12 comes from the fact that the 180 degree meridian is 12 hours away from Greenwich, which is a different idea altogether.
- (b)You will gain 12 hours — Same error in the opposite direction — no crossing of the Date Line changes the reckoning by 12 hours.
- (c)You will gain 24 hours — This is the change for the opposite journey. Flying westward across the line takes you to the side where the date is later, so a day is added rather than subtracted.
The International Date Line runs roughly along the 180 degree meridian, bending around island groups and territories so that a single country is not split between two dates. It is the seam of the calendar — the place where one date ends and the next begins. Crossing it always changes the date by exactly one day, in the direction opposite to the crossing.
Read the options as a statement about what happens to the date, not about how the journey feels. Because the eastern side of the line runs one day behind the western side, an eastward crossing subtracts a day and a westward crossing adds one. Some textbooks describe the eastward crossing instead as gaining a day, on the reasoning that you live through the same calendar date twice. Both descriptions point at the same arithmetic — the calendar is put back 24 hours — and the paper's key follows the subtraction wording, so the answer stays 24 hours rather than 12 either way.
- The International Date Line follows roughly the 180 degree meridian, deviating to avoid splitting land areas and island groups.
- The date on the eastern side of the line is one day earlier than the date on its western side.
- Crossing the line always changes the date by a full day, never by a half day.
- The line passes through the Bering Strait, between the two Diomede Islands.
An eastward crossing subtracts a whole day, which gives option (d).
- Reaching for 12 hours because 180 degrees is 12 hours from Greenwich.
- Reversing the direction — the eastward crossing subtracts a day, the westward crossing adds one.
A direction-and-effect item on the Date Line; fix the east side as the earlier date and the rest follows.
Which one of the following straits is nearest to the International Date Line?
- (a) Malacca Strait
- (b) Bering Strait
- (c) Strait of Florida
- (d) Strait of Gibraltar
Answer(b) Bering Strait
Tests the course of the same Date Line from the map side — it threads the Bering Strait between the Diomede Islands.
Consider the following statements regarding the International Date Line: 1. It is roughly 180° meridian, which deviates slightly East and West to avoid land areas surrounded by the Atlantic Ocean. 2. The date to the East of this line is (24 hours) earlier than to the West. Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer(b) 2 only
That NDA item states the very rule this question applies — east of the line the date is 24 hours earlier — and rejects the claim that the line bends around Atlantic land.
- practice — not a real PYQ
The International Date Line broadly follows which meridian?
- (a)0 degrees
- (b)90 degrees east
- (c)180 degrees
- (d)82 degrees 30 minutes east
Answer(c) 180 degrees — with deviations so that island groups and territories are not split between two dates.
- practice — not a real PYQ
A ship sailing westward across the International Date Line must
- (a)add one day to the date
- (b)subtract one day from the date
- (c)add 12 hours to the clock
- (d)make no change at all
Answer(a) add one day to the date — the western side of the line keeps the later date.