Levelling staff graduations – counting the smallest divisions per metre On a standard levelling staff used in engineering surveys, how many subdivisions are there per metre length?

Introduction / Context:
Levelling staffs for general engineering surveys are typically metric with bold decimetre markings and centimetre subdivisions. Reading and recording staff values correctly depends on recognizing the scale of these graduations. This question asks you to identify the number of subdivisions per metre on a conventional staff.

Given Data / Assumptions:

• Standard metric staves are considered (E-type or similar).
• Smallest routine graduation is 1 cm (0.01 m).
• We count the number of such subdivisions within 1 metre.

Concept / Approach:

If the smallest marked subdivision is one centimetre, each metre contains 100 equal parts. The large black–red patterning aids quick decimetre recognition, but the fine reading is at 1 cm. Vernier attachments may provide millimetre interpolation in precise levelling, yet the basic staff subdivision count remains 100 per metre.

Step-by-Step Solution:

Verification / Alternative check:

Manufacturers’ catalogues for metric levelling staffs list centimetre divisions with decimetre blocks and metre numerals, confirming 100 subdivisions per metre.

Why Other Options Are Wrong:

200, 500, 1000 would imply 5 mm, 2 mm, or 1 mm base divisions respectively; those are not standard base subdivisions for typical engineering staves.

Common Pitfalls:

Confusing basic staff graduations with vernier resolution; misreading inverted figures on E-type staffs leading to transcription errors.

Final Answer:

100