Question

Read the following statements regarding Theodolite
Statement I: It can measure both horizontal and Vertical angles
Statement II: Plumb bob is used for centering of theodolite
In light of the above statements, choose the correct answer from the options given below

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Hint:

The setup of a theodolite always involves three key steps:
1. Centering: Aligning the instrument over the station point using a plumb bob or optical plummet.
2. Levelling: Making the vertical axis truly vertical using plate levels.
3. Focusing: Eliminating parallax error.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A theodolite is a precision optical instrument used in surveying.
It is designed to measure angles between visible points in both horizontal and vertical planes.
Detailed Explanation:
Let us analyze Statement I:
The theodolite features two graduated circles:
- A horizontal circle to measure horizontal angles (azimuth).
- A vertical circle to measure vertical angles (altitude or elevation/depression).
This dual capability is the defining feature of a theodolite, allowing surveyors to map coordinates in three dimensions.
Thus, Statement I is true.
Let us analyze Statement II:
To obtain accurate measurements, the theodolite must be set up directly over the surveyed station point.
This alignment process is called centering.
Surveyors suspend a plumb bob (a heavy pointed weight on a string) from a hook beneath the vertical axis of the instrument to locate the exact point on the ground.
(Modern instruments may also use an optical or laser plummet for this purpose).
Thus, Statement II is true.

Step 2: Final Answer:
Both Statement I and Statement II are true.