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Q41 (NDA-I/2009) Geography › World Physical Geography › Earth rotation and time Answer Verified

Which one of the following is the difference in local time between the places located at 165° East and 165° West?

Result
Your answer:  ·  Correct: C
Explanation

The Earth rotates 360° in 24 hours, which translates to 15° per hour or 1° every 4 minutes [c2][t6]. To find the time difference between 165°E and 165°W, we calculate the longitudinal distance. Since they are in different hemispheres, we add the degrees: 165° + 165° = 330° [t2]. Dividing 330° by 15° per hour results in a 22-hour time difference. Alternatively, one can calculate the distance via the International Date Line (180°): 165°E is 15° (1 hour) west of the 180° meridian, and 165°W is 15° (1 hour) east of it. Thus, 165°E is 11 hours ahead of GMT, while 165°W is 11 hours behind GMT [c2][t8]. The total difference is 11 + 11 = 22 hours. This confirms that while they are close to the same date line, their local times differ by 22 hours [t4].

Sources

  1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 18: Latitudes and Longitudes > Longitude and Time > p. 243
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