Question

Describe the lines of longitude and state their use in relation to distance and time.

Answer 1

Longitude is the angular distance of a place east or we§t of the Prime Meridian or 0° longitude.
The lines of longitude are the great semi-circles joining North pole and South pole and are equal in length. These are 0° – 180°E and 0° – 180°W longitudes or total 360°. As the earth takes 24 hours to make a complete rotation along its axis crossing 360° lines of longitude, so earth takes nearly 4 minutes to move one degree (1 °) longitude or 111 km length or distance. There is a difference in time of one hour between 15° interval of longitudes. According to the clock-time, EGA stands for East-Gain-Add and WLS means West Lose Subtract. In other words for every 10 longitudes towards east 4 minutes are to be added and towards west for each 1° longitude 4 minutes are to be subtracted.