The Zenith is/are

Question

Question

This question was previously asked in

ESE Civil 2021 Official Paper

the point on the upper portion of the celestial sphere marked by plumb line above the observer.
the point on the lower portion of the celestial sphere marked by plumb line below the observer.
the two points in which the Earth’s axis of rotation meets the Earth’s sphere.
the great circle of the Earth, the plane of which is at right angles to the axis of rotation.

Answer 1

Explanation:

Zenith:

If a plumb line through an observer is extended upward, the imaginary point at which it appears to intersect the celestial sphere is known as Zenith.

Additional Information

Nadir point:

The imaginary point at which it appears to intersect downward in the celestial sphere is known as Nadir.

Pole:

If the axis of rotation of the earth is imagined to be extended infinitely in both directions, the points at which it meets the celestial sphere are known as poles.
The point of intersection in the northern hemisphere is known as the north celestial pole and that in the southern hemisphere as the south celestial pole.

Celestial point:

An imaginary sphere of infinite radius with the earth at its center and other celestial bodies studded on its inside surface is known as the celestial sphere.