Sample 1Medium
A vernier calliper has a main scale in millimetres, and 10 vernier divisions equal 9 main-scale divisions. It has no zero error. In the figure, with a cylinder between the jaws, the vernier zero lies just past the 23 mm mark of the main scale, and the 6th vernier division lines up with a main-scale mark. What is the diameter of the cylinder?
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The answer is B.
Least count = 1 MSD − 1 VSD = 1 mm − 0.9 mm = 0.1 mm. Reading = 23 mm + 6 × 0.1 mm = 23.6 mm = 2.36 cm.
- A.
2.30 cm ignores the vernier coincidence.
- C.
2.96 cm adds 6 × 0.9 mm (the vernier division) instead of 6 × least count.
- D.
2.46 cm misreads the main scale as 24 mm; the vernier zero is just past 23 mm.
NCERT: Class 11 Physics Laboratory Manual, Vernier callipers