Question

With regard to the theodolite, which one of the following statements is correct?

• A. the axis of the plate level should be parallel to the vertical axis
• B. the axis of striding level must be parallel to the horizontal axis
• C. the axis of the altitude level must be perpendicular to the line of collimation
• D. the line of collimation must be perpendicular to the plate level axis

Hint:

Correct theodolite setup: collimation line ⟂ plate level axis.

Answer 1

The Correct Option is D

In the context of a theodolite, it is crucial to understand the relationship between its various axes and components to ensure accurate measurements. Let's analyze the provided options:

• Option 1: The axis of the plate level should be parallel to the vertical axis. This statement is incorrect because the plate level ensures the horizontal alignment of the theodolite in its initial setup and does not relate directly to the vertical axis.
• Option 2: The axis of striding level must be parallel to the horizontal axis. While the striding level is used to ensure the horizontal axis remains horizontal, this statement is not the standard statement relevant to the theodolite's geometric conditions.
• Option 3: The axis of the altitude level must be perpendicular to the line of collimation. This statement does not apply directly as the altitude level in many cases is applicable when using telescopic sights, which is a slightly different context.
• Option 4: The line of collimation must be perpendicular to the plate level axis. This is the correct statement as it directly relates to the proper functioning of a theodolite. To ensure accurate angle measurements, the line of collimation should be perpendicular to the vertical (or plate) axis. This ensures that the readings on the horizontal circle are true.

Therefore, the correct answer is: the line of collimation must be perpendicular to the plate level axis.