Physical World Units and Measurements - Result Question 42

43. The main scale of a vernier callipers has $n$ divisions/cm. $n$ divisions of the vernier scale coincide with $(n-1)$ divisions of main scale. The least count of the vernier callipers is,

[NEET Odisha, 2019]

(a) $\frac{1}{n(n+1)} cm$

(b) $\frac{1}{(n+1)(n-1)} cm$

(c) $\frac{1}{n} cm$

(d) $\frac{1}{n^{2}} cm$

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Answer:

Correct Answer: 43. (d)

Solution:

  1. (d) $n VSD=(n-1) MSD$

$1 VSD=\frac{(n-1)}{n} MSD$

L.C. $=1 MSD-1 VSD=1 MSD-\frac{(n-1)}{n} MSD$

$=\frac{1}{n} MSD=\frac{1}{n} \times \frac{1}{n}=\frac{1}{n^{2}}$