Question map
How much of the time period 15 of longitudes account for?
Explanation
The Earth completes one full rotation of 360° on its axis in approximately 24 hours [c1][c2]. To determine the time accounted for by a specific degree of longitude, the total time (1,440 minutes) is divided by the total degrees (360°), resulting in a rate of 4 minutes per 1° of longitude [t3][t7]. Consequently, a 15° change in longitude corresponds to a time difference of 60 minutes (15° × 4 minutes = 60 minutes), which is equivalent to one hour [c1][c5]. This mathematical relationship forms the basis of global time zones, where each 15° interval east or west of the Prime Meridian represents a one-hour advancement or retardation of local time, respectively [c2][c5]. Therefore, 15° of longitude accounts for exactly 60 minutes.
Sources
- [1] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 2: The Earth's Crust > Longitude and Time > p. 11
- [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 18: Latitudes and Longitudes > Longitude and Time > p. 243
- [3] Exploring Society:India and Beyond. Social Science-Class VI . NCERT(Revised ed 2025) > Chapter 1: Locating Places on the Earth > Understanding Time Zones > p. 20