Vernier Callipers NEET 2026: Least Count of 0.02 cm

What is the answer to the Vernier Callipers NEET 2026 question?

Option C, 0.02 cm, is correct for the Vernier Callipers NEET 2026 question. Twenty divisions on a vernier scale span the same length as sixteen main-scale divisions; each main-scale division measures 1 mm. Determine the instrument’s least count.

This is a Physics and Measurement question in single-correct format, rated medium on this question bank’s scale. The target solving time is 60 seconds.

You need the difference between one main-scale division and one vernier-scale division. No object reading or zero-error correction is required here.

How do you find one VSD from twenty VSD equalling sixteen MSD?

This is the official solution’s starting formula. MSD means main-scale division, and VSD means vernier-scale division. One VSD is 0.8 mm long, obtained by dividing the supplied total length by the number of vernier divisions.

The given equality compares the total lengths of two groups of divisions:

Divide both sides by twenty to obtain the length of a single vernier division:

Now use the stated main-scale division length:

Twenty vernier divisions collectively span 16 mm. One vernier division is not 16 mm long: that length belongs to the full group of twenty. Divide first because the least-count formula compares single divisions, not the groups.

How does the subtraction give a least count of 0.02 cm?

The subtraction gives 0.2 mm, which converts to 0.02 cm, option C. Keep the fractional step visible: the supplied scale relationship determines the subtraction.

Substitute the length of one VSD into the official formula:

Since one MSD measures 1 mm:

Convert only after completing the subtraction. A centimetre contains ten millimetres, so divide the millimetre value by ten:

A quick check confirms the subtraction:

Do not divide one MSD by the number of vernier divisions automatically. The familiar shortcut assumes this specific relationship:

Here, twenty VSD equal sixteen MSD, not nineteen MSD. That shortcut does not apply. Use the supplied lengths first, then subtract.

How does a unit-conversion mistake produce option A?

Option A results if you calculate 0.2 mm correctly, then write 0.2 cm without converting the numerical value. Changing only the unit label changes the physical length.

The incorrect chain is:

Compare the actual lengths:

Option A is ten times the correct value. It cannot equal the difference between 1 mm and 0.8 mm.

Keep the subtraction in millimetres, write the conversion factor explicitly, and only then match an option. This checks the numerical value and the unit together:

The millimetre units cancel, leaving centimetres. The physical length stays the same even though its numerical value changes.

How do you solve three related Physics and Measurement questions?

Use the division-first method for the next two least-count problems. For the reading problem, add the vernier contribution, then subtract the signed zero error. All three are original practice questions from Physics and Measurement, not verified NEET PYQs.

Question 1: Ten VSD span nine MSD, and each MSD measures 1 mm. Find the least count in millimetres and centimetres.

Question 2: Twenty-five VSD span twenty-four MSD, and each MSD measures 1 mm. Find the least count.

Question 3: Using the original instrument, find the corrected measurement when the main-scale reading is 12 mm, the third vernier division coincides, and the positive zero error is 0.2 mm.

The original least count is 0.2 mm. MSR means main-scale reading:

A positive zero error means the instrument reads too high, so subtract it. For every least-count calculation, follow this sequence: obtain one VSD, subtract from one MSD, then convert units.

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