A vernier calipers has 1 ~mm marks on the main scale. It has 20...

A vernier calipers has

1 \mathrm{~mm}

marks on the main scale. It has 20 equal divisions on the vernier scale which match with 16 main scale divisions. For this vernier calipers, the least count is

Options

A $0.02 \mathrm{~mm}$
B $0.05 \mathrm{~mm}$
C $0.1 \mathrm{~mm}$
D $0.2 \mathrm{~mm}$

Correct answer

D. $0.2 \mathrm{~mm}$

Step-by-step solution

Least count of vernier calipers

\begin{aligned}& \text{ LC }=1 \mathrm{MSD}-1 \text{ VSD }\\ & =\frac{\text{ Smallest division on main scale }}{\text{ Number of divisions on vernier scale }}\\ & 20 \text{ divisions of vernier scale }\\ & =16 \text{ divisions of main scale }\\ & \therefore \quad 1\mathrm{VSD}=\frac{16}{20} \mathrm{~mm}=0.8 \mathrm{~mm}\\ & \therefore \quad \text{ LC }=1 \mathrm{MSD}-1 \mathrm{VSD}\\ & =1 \mathrm{~mm}-0.8 \mathrm{~mm}\\ & \therefore \quad=0.2 \mathrm{~mm}\\ & \end{aligned}

\therefore The correct option is (d).

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