The correct option is (a).
Explanation
The Earth has two primary types of motion: rotation and revolution. These motions are responsible for phenomena such as day and night, seasons, and the measurement of time.Statement-wise Analysis:
- Statement 1 is Correct: Rotation is defined as the movement of the Earth on its axis. The Earth rotates from west to east, which takes approximately 24 hours to complete one rotation. This motion is the primary cause of the cycle of day and night.
- Statement 2 is Incorrect: Revolution is the movement of the Earth around the Sun in a fixed path or orbit. However, this orbit is elliptical (oval-shaped), not perfectly circular. It takes 365¼ days for the Earth to complete one revolution.
- Statement 3 is Incorrect: The axis of the Earth is an imaginary line that runs through the center of the Earth connecting the North and South Poles. It is not a physical line. Furthermore, this imaginary axis is tilted at an angle of 66½° with the plane of its orbit.
Key Takeaway: The Earth's axis is an imaginary line, and its orbit around the Sun is elliptical, not circular. Rotation refers to spinning on the axis, while revolution refers to orbiting the Sun.