Fundamentals of Surveying (FS) Practice Exam

Which of the following can cause a constant error observed in repeated measurements?

1. Instrument error

2. Measurement conditions

3. Observer fatigue

4. Random choice

The correct answer is: Instrument error

A constant error in repeated measurements often arises from systematic inaccuracies that consistently affect the results in the same way. Instrument error is a type of systematic error that can occur due to flaws in the instrument being used. For example, if a surveying instrument is miscalibrated or has a bias in its readings, it will consistently produce readings that are higher or lower than the true values, leading to a constant error in all measurements taken with that instrument. On the other hand, measurement conditions, observer fatigue, and random choice are factors that can introduce variability or different levels of error in measurements, rather than consistent errors across repeated measurements. Measurement conditions can vary due to environmental factors like temperature or atmospheric pressure, observer fatigue can lead to inconsistent performance over time, and random choice can lead to inconsistent errors that do not show a constant pattern. Hence, these factors are not responsible for the constant errors seen in repeated measurements as instrument error is.