This question was popular among the candidates and quite a good percentage of those who answered the question were able to draw a diagram illustrating the eclipse and explained what it was. However, a significant percentage of those who answered it were not able to state the characteristics and uses of Great Circle. The characteristics of Great Circle are:
-           imaginary circular lines drawn on maps or globes
-           they run in all directions
-           they are limitless in number
-           any line that divides the earth into two equal parts is a Great Circle
-           the centre of Great Circles is also the centre of earth
-           the Equator is the only latitude that is a Great Circle
-           the shortest distance between any two points on the earth’s surface lies along the circumference of the Great Circle
-           it is capable of dividing the earth into two equal halves
-           each halve is called hemisphere
-           any two opposite longitudes form a Great Circle, e.g. Longitudes 900E & 900W; 180o &  00
-           they are equal in length
The uses of Great Circles are:
-           for locating places on the earth’s surface
-           in determining approximate distances between places
-           serves as the shortest distance between two points on the earth’s surface
-           in determining directions
-           by commercial aircrafts for long distance journeys
-           in saving time in aviation and navigation
-           by ship for navigation
-           in cutting fuel cost in aviation and navigation