Fundamentals of Surveying (FS) Practice Exam

Which device typically defines the line of sight in modern surveying?

1. bull's-eye bubble

2. compensator

3. plumb bob

4. spirit level bubble

The correct answer is: compensator

The device that typically defines the line of sight in modern surveying is the compensator. A compensator is an essential component in instruments such as total stations and theodolites, where it automatically adjusts for any tilt or angular misalignment of the instrument. This capability allows the surveyor to maintain an accurate line of sight to a target, even on uneven terrain. When the compensator is active, it ensures that the line of sight remains level, facilitating precise angle measurements and distance readings. The bull’s-eye bubble, while helpful for leveling the instrument before taking measurements, does not actively maintain the line of sight during surveying. Similarly, a plumb bob is used to establish a vertical reference point but does not have any role in defining the horizontal line of sight. A spirit level bubble can assist in leveling the instrument but does not provide the dynamic corrections that a compensator offers for maintaining accuracy when measuring angles and distances.