Question

Which latitude is called a great circle?
(A) Equator
(B) 66 ½° N
(C) 20° S
(D) 23 ½° S

Answer 1

Hint: The angular distances East or West of the Equator are called latitudes, also known as parallels. Any circle that circumnavigates the Earth and passes through the centre of the Earth is called a great circle. The lines that do not pass through the centre of the earth are the small circles.

Complete answer:The great circle is the largest possible circle that can be drawn around a sphere. All spheres are having great circles. When a sphere is divided at one of its great circles, it is like cutting into two halves. A great circle has the same boundary and same centre point as its sphere. Great circles are seen on all meridians on Earth. All the lines of longitude meet at the poles, intersecting the Earth in half.
Thus a great circle always splits the Earth into two halves, so that the Equator is a great circle. All latitudes other than 0° are small circles. All lines of longitude are great circles and all latitudes are small circles except the Equator. The only east-west line which is also a great circle is the Equator.
66 ½° North is a parallel of latitude which denotes the Arctic Circle. 20° South is the circle of latitude which is 20 degrees south of the Earth's equatorial plane. 23 ½° South denotes the Tropic of Capricorn. Since the Equator is of zero degrees latitude, it is the great circle.

Thus, the option (A) is correct.

Note: The shortest distance in between any two points on the surface of Earth is attained along the curve of a great circle. All the other lines of latitude get smaller as it gets nearer to the poles.