Q.
N divisions on the main scale of a vernier calliper coincide with (N+1) divisions of the vernier scale. If each division of main scale is ′a′ units, then the least count of the instrument is
4252
198
AIEEEAIEEE 2012Physical World, Units and Measurements
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Solution:
No of divisions on main scale =N
No of divisions on vernier scale =N+1
size of main scale division =a
Let size of vernier scale division be b then we have aN=b(N+1)⇒b=N+1aN
Least count is a−b=a−N+1aN =a[N+1N+1−N]=N+1a