Caliper Assessment Vernier Measurement 5 — Questions and Answers
Question 1: A vernier caliper is used to measure a gauge block known to be exactly 50.000 mm. The caliper reads 50.04 mm. This instrument has a systematic error of:
- +0.04 mm (Correct answer)
- −0.04 mm
- +0.40 mm
- 0.00 mm
Correct answer: +0.04 mm
The caliper over-reads by 50.04 − 50.00 = +0.04 mm, indicating a positive systematic error.
Question 2: When using a vernier caliper to measure the groove width on a shaft, which jaw orientation is correct?
- Lower jaws placed across the groove opening to measure as an external dimension
- Upper jaws inserted into the groove to measure as an internal dimension (Correct answer)
- Depth rod inserted into the groove
- Either jaw set can be used interchangeably
Correct answer: Upper jaws inserted into the groove to measure as an internal dimension
A groove's width is an internal (inside) dimension measured by inserting the upper (inside) jaws into the groove.
Question 3: The abbreviation 'MSD' in vernier caliper theory stands for:
- Main Scale Division (Correct answer)
- Metric Standard Division
- Measured Scale Displacement
- Minimum Scale Distance
Correct answer: Main Scale Division
MSD stands for Main Scale Division, the spacing between consecutive graduations on the fixed main scale.
Question 4: If a 25-division vernier caliper has a positive zero error where the 5th vernier line coincides, and a raw reading shows the 12th vernier line coinciding with a main scale of 18 mm, what is the corrected reading?
- 18.28 mm (Correct answer)
- 18.48 mm
- 18.68 mm
- 17.48 mm
Correct answer: 18.28 mm
LC = 0.04 mm; raw reading = 18 + (12×0.04) = 18.48 mm; zero error = 5×0.04 = 0.20 mm; corrected = 18.48 − 0.20 = 18.28 mm.
Question 5: In a Caliper Assessment cognitive test, 'vernier measurement' questions most often test:
- The ability to accurately read and interpret a scaled diagram under time pressure (Correct answer)
- Memorization of caliper part names only
- Ability to convert units without a scale
- Knowledge of digital caliper electronics
Correct answer: The ability to accurately read and interpret a scaled diagram under time pressure
Caliper Assessment aptitude tests evaluate numerical reasoning and the ability to extract precise values from scale diagrams quickly.
Question 6: A caliper reads 0.000 mm with jaws closed, but when a 10.00 mm gauge block is inserted it reads 10.02 mm. This is best described as:
- Positive systematic error of 0.02 mm (Correct answer)
- Random error
- Negative zero error
- Calibration tolerance within spec
Correct answer: Positive systematic error of 0.02 mm
The instrument consistently over-reads by 0.02 mm across its range, which is a positive systematic error requiring correction or recalibration.
Question 7: Which maintenance practice BEST preserves a vernier caliper's accuracy over time?
- Wiping the jaws and scales with a clean, lightly oiled cloth after each use and storing in its case (Correct answer)
- Submerging in solvent weekly to remove debris
- Storing it open-jawed to avoid jaw deformation
- Calibrating it only when a reading seems wrong
Correct answer: Wiping the jaws and scales with a clean, lightly oiled cloth after each use and storing in its case
Regular cleaning with a lightly oiled cloth prevents corrosion and debris buildup, maintaining jaw and scale integrity.
Caliper Assessment Vernier Measurement 5
A vernier caliper is used to measure a gauge block known to be exactly 50.000 mm.
The caliper reads 50.04 mm.
This instrument has a systematic error of: