Question

Which of the following error is not a systematic error?

• A. Error induced due to stylus pressure
• B. Instrument location errors
• C. Error due to parallax
• D. Error due to play in the instrument's linkages

Hint:

Systematic vs. Random Errors. Systematic errors are consistent biases (e.g., calibration, environmental effects, consistent parallax). Random errors are unpredictable variations. Backlash/play often introduces non-systematic inconsistencies.

Answer 1

The Correct Option is D

Systematic errors are errors that are consistent and repeatable, causing measurements to be consistently higher or lower than the true value
Random errors are unpredictable and fluctuate

(1) Error induced due to stylus pressure: If the pressure applied is consistently too high or too low, it can introduce a systematic error in measurements (e
g
, deformation)

(2) Instrument location errors: Environmental factors specific to a location (temperature, humidity, vibrations, magnetic fields) can cause systematic deviations if the instrument is calibrated or used under different conditions

(3) Error due to parallax: While parallax error *can* be random if the observer's eye position varies unpredictably, it becomes a systematic error if the observer consistently views the scale from an incorrect angle
Often listed as a potential systematic error

(4) Error due to play (backlash) in instrument linkages: Mechanical play or looseness in linkages often leads to inconsistent readings depending on the direction of measurement approach
The error is not constant or consistently biased in one direction; it's often unpredictable or history-dependent (hysteresis), making it not purely systematic
It contributes to uncertainty and inconsistency, aligning more closely with non-systematic or random components
Therefore, error due to play is the least likely to be a purely systematic error among the choices