Question

If the altitude bubble is provided both on the index frame as well as on the telescope of a theodolite, then the instrument is levelled with reference to the:

• A. altitude bubble on the telescope
• B. altitude bubble on the index frame, if it is to be used as a level
• C. altitude bubble on the telescope, if it is to be used as a level
• D. laser principle

Hint:

Use index frame bubble when theodolite serves as a level.

Answer 1

The Correct Option is B

When leveling a theodolite, especially one equipped with altitude bubbles on both the index frame and the telescope, it is essential to know which bubble to reference. The key point is:

The theodolite should be leveled with reference to the altitude bubble on the index frame, provided it is intended to be used as a level. This is critical because:

• The altitude bubble on the index frame ensures that the instrument is correctly oriented with respect to the horizontal plane.
• If this bubble is used, the measured angles and observations will be accurate and reliable, as the bubble is designed to align the entire instrument plane.
• Using the index frame's altitude bubble as a level helps in maintaining consistency and precision in measurements across various observations.

Hence, in cases where the theodolite has dual altitude bubbles, always prioritize the bubble on the index frame for leveling to ensure proper alignment and operational accuracy.