Vernier Measurement Flashcards
21 cards from real Caliper Assessment practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 20 Vernier Measurement flashcards as text
A vernier caliper has a main scale reading of 23 mm and the 6th vernier division aligns with a main scale line. If the vernier has 25 divisions equal to 24 mm, what is the measurement?
Answer: 23.24 mm
The least count is 1/25 mm = 0.04 mm, so 6 × 0.04 = 0.24 mm, giving 23 + 0.24 = 23.24 mm.
Which part of a vernier caliper is used specifically to measure the internal diameter of a hollow object?
Answer: Upper jaws
The upper (inside) jaws are designed to measure internal dimensions such as bore diameters.
A metric vernier caliper reads 47.35 mm. When converted to inches (1 inch = 25.4 mm), what is the nearest correct reading?
Answer: 1.864 in
47.35 ÷ 25.4 ≈ 1.864 inches.
What does 'parallax error' mean in the context of reading a vernier caliper?
Answer: Error from reading the scale at an angle rather than straight on
Parallax error occurs when the observer's line of sight is not perpendicular to the scale, causing an apparent shift in the reading.
On a 50-division vernier caliper (50 vernier divisions = 49 mm), what is the least count?
Answer: 0.02 mm
Least count = 1 mm − (49/50) mm = 1 − 0.98 = 0.02 mm.
When measuring a cylindrical rod's outside diameter with a vernier caliper, the rod should be placed:
Answer: Perpendicular to the jaws, fully seated at their base
Placing the rod fully and perpendicularly seated at the jaw base ensures accurate, repeatable diameter measurement.
A vernier caliper's depth rod reads 8 mm on the main scale, and the 4th vernier line coincides on a 10-division vernier. What is the depth?
Answer: 8.40 mm
Least count = 1/10 = 0.1 mm; depth = 8 + (4 × 0.1) = 8.4 mm (written as 8.40 mm to show precision).
If the zero of the vernier scale is to the LEFT of the zero of the main scale when the caliper is closed, the instrument has:
Answer: Negative zero error
When the vernier zero falls left of the main scale zero, the caliper reads less than the true value — this is negative zero error.
A machinist measures the same part five times with a vernier caliper and gets: 12.14, 12.16, 12.14, 12.15, 12.15 mm. What is the average reading?
Answer: 12.148 mm
(12.14+12.16+12.14+12.15+12.15) ÷ 5 = 60.74 ÷ 5 = 12.148 mm.
Which vernier caliper graduation allows the finest possible resolution?
Answer: 50-division vernier (0.02 mm)
A 50-division vernier yields the smallest least count of 0.02 mm among the common types listed.
A technician corrects for a positive zero error of +0.06 mm. The uncorrected reading is 25.34 mm. What is the true measurement?
Answer: 25.28 mm
True value = uncorrected reading − positive zero error = 25.34 − 0.06 = 25.28 mm.
On an inch-based vernier caliper with 25 vernier divisions spanning 0.600 inch (main divisions = 1/16 in), what is the least count in inches?
Answer: 0.001 in
Standard inch vernier calipers are typically graduated to 0.001 inch (25 divisions over 0.025 inch range).
What is the purpose of the locking screw (or thumb screw) on a vernier caliper?
Answer: To fix the slide in place so the reading doesn't change while the caliper is removed from the workpiece
The locking screw holds the slider stationary so the measurement can be read after removing the caliper from the part.
Which scenario would most likely INVALIDATE a vernier caliper measurement?
Answer: Measuring a hot workpiece immediately after machining
Thermal expansion of a hot part will cause the measurement to differ from the part's true dimension at standard temperature (68°F/20°C).
On a vernier caliper, the main scale reads 31 mm and the 18th vernier line aligns on a 20-division vernier. What is the measurement?
Answer: 31.90 mm
Least count = 1/20 = 0.05 mm; reading = 31 + (18 × 0.05) = 31 + 0.90 = 31.90 mm.
The vernier scale was invented by:
Answer: Pierre Vernier
Pierre Vernier, a French mathematician, invented the vernier scale in 1631.
A step measurement using a vernier caliper involves:
Answer: Measuring the height difference between two surfaces at different levels
Step measurements use the lower jaw tips to find the height difference between two parallel surfaces at different elevations.
When vernier caliper jaws show measurable wear at the tips, the instrument should be:
Answer: Sent for recalibration or replaced
Worn jaws reduce accuracy and cannot be reliably corrected in the field; the instrument needs professional recalibration or replacement.
Which of the following correctly describes how to read the vernier scale?
Answer: Find the vernier line that most closely aligns with any main scale line
The correct technique is to identify the single vernier graduation that aligns exactly (or most closely) with a main scale graduation.
A caliper assessment test question shows a vernier with the main scale at 7 cm 3 mm and vernier division 7 aligned on a 10-division scale. What is the reading?
Answer: 7.37 cm
73 mm main scale + (7 × 0.1) mm = 73.7 mm = 7.37 cm (both 73.7 mm and 7.37 cm are correct; 7.37 cm matches option B).
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Sources & references
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