Physical World Units and Measurements - Result Question 48
49. In a vernier calliper $N$ divisions of vernier scale coincides with $(N-1)$ divisions of main scale (in which length of one division is $1 mm$ ). The least count of the instrument should be [1994]
(a) $N$
(b) $N-1$
(c) $1 / 10 N$
(d) $1 / N-1$
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Answer:
Correct Answer: 49. (c)
Solution:
- (c) Least count = 1MSD - 1 VSD
$=1 MSD-(\frac{N-1}{N}) MSD$ $=\frac{1}{N} MSD=\frac{1}{N} \times \frac{1}{10} cm=\frac{1}{10 N}$
Smaller value of the least count, higher is the accuracy of measurement. Accuracy of measurement is higher when number of significant figure after the decimal in measurement is larger.
