Q1.Consider the following statements regarding the International Date Line (IDL):
- The IDL is an exact straight line following the $180^\circ$ meridian from the North Pole to the South Pole.
- A traveler crossing the IDL from West to East gains a day (repeats the same date).
- The IDL deviates at the Bering Strait to keep all of Siberia in the same time zone.
Which of the statements given above is/are correct?
A) 1 and 2 only
B) 2 and 3 only
C) 3 only
D) 1, 2, and 3
Correct Answer: B) 2 and 3 only
Explanation:
- Statement 1 : Incorrect. The IDL is not a straight line; it zig-zags to avoid splitting countries and island groups.
- Statement 2 : Correct. Crossing from West → East (Asia → Americas) means you gain a day (repeat the same date).
- Statement 3 : Correct. The IDL bends near the Bering Strait to keep regions like Siberia within the same calendar day.
Q2.If the time at the Prime Meridian (0) is 12:00 PM (Noon) on Thursday, what will be the local time and day at a location situated at 75 East longitude?
A) 5:00 AM, Thursday
B) 5:00 PM, Thursday
C) 7:00 PM, Thursday
D) 5:00 PM, Wednesday
Correct Answer: B) 5:00 PM, Thursday
Explanation:
- Earth rotates 360° in 24 hours → 15° per hour.
- Time difference = 75
75∘÷15=5 hours. - Since the location is East, we add time (E.G.A: East–Gains–Add).
12:00 PM+5 hours=5:00 PM
Same day (Thursday), later time.
Q3.
Assertion (A): Places located to the East of a given meridian have a later time than places to the West.
Reason (R): The Earth rotates from West to East, causing eastern longitudes to see the sun earlier.
Select the correct answer:
A) Both A and R are true, and R is the correct explanation of A.
B) Both A and R are true, but R is NOT the correct explanation of A.
C) A is true, but R is false.
D) A is false, but R is true.
Correct Answer: A
Explanation:
- Assertion : True. Eastern locations have later (ahead) time.
- Reason : True. Earth rotates West → East, so eastern places experience sunrise earlier.
- The reason directly explains the assertion, making option A correct.
Q4.A ship leaves Yokohama (Japan, $140^\circ$ E) at 10:00 AM on Monday and travels toward San Francisco ($122^\circ$ W). Upon crossing the International Date Line ($180^\circ$):
A) The clock is advanced by 24 hours.
B) The clock is set back by 24 hours.
C) Only the hour changes based on the nearest time zone.
D) The date remains the same, but the time is adjusted by 12 hours.
Correct Answer: B) The clock is set back by 24 hours
Explanation:
- Travel direction: West → East (Asia → America).
- Crossing the IDL in this direction means:
- You subtract one day (−24 hours).
- So, Monday becomes Sunday (same clock time, previous date).
Q5.Which of the following countries has the highest number of time zones?
A) Russia
B) USA
C) France
D) China
Correct Answer: C) France
Explanation:
- France has 12 time zones, the highest in the world.
- This is due to its overseas territories spread across different oceans.
- Russia and the United States each have 11 time zones.
- China officially uses only one time zone despite its large size.
