Question

circle of illumination is a great circle​

Answer 1

Circle of Illumination: Sun illuminates one half of the earth at any given moment. The edge of the sunlit hemisphere called the circle of illumination is a great circle that divides the earth into light half and dark half.

Answer 2

Answer:

Of all the parallels equator alone makes a great circle. ... The edge of the sunlit hemisphere called the circle of illumination is a great circle that divides the earth into light half and dark half.