A theodolite is called a transit theodolite, when its telescope can be revolved through a complete revolution about its
- AVertical axis in an inclined plane
- BHorizontal axis in an inclined plane
- CVertical axis in a horizontal plane
- DHorizontal axis in a vertical planeCorrect
Solution
Concept
Transit Theodolite Properties
Formula
N/A
Step-by-step solution
1. Understand the property of transiting in a theodolite. 2. Note that transiting allows the telescope to revolve completely in a vertical plane. 3. Identify that this complete rotation occurs about its horizontal axis.
Explanation
A transit theodolite is a surveying instrument whose telescope can be fully rotated 360 degrees in a vertical plane around its horizontal axis (also called the trunnion axis). This complete rotation allows the line of sight to be reversed easily without changing the position of the instrument.
Shortcut
To remember the movement of a Transit Theodolite, use the trick "Horizontal Axis, Vertical Plane" (H-V): - Transiting: Revolves about the Horizontal axis in a Vertical plane (like a ferris wheel). - Swinging: Rotates about the Vertical axis in a Horizontal plane (like a merry-go-round).
Common mistake
A common mistake is confusing the axis of rotation with the plane of motion, leading students to select option C by confusing rotation about the vertical axis with motion in the vertical plane. Another frequent error is mixing up transiting (revolving about the horizontal axis in a vertical plane) with swinging (rotating about the vertical axis in a horizontal plane).
Correct answer: D) Horizontal axis in a vertical plane