JEE MAIN - Physics (2024 - 6th April Evening Shift - No. 7)
In a vernier calliper, when both jaws touch each other, zero of the vernier scale shifts towards left and its $$4^{\text {th }}$$ division coincides exactly with a certain division on main scale. If 50 vernier scale divisions equal to 49 main scale divisions and zero error in the instrument is $$0.04 \mathrm{~mm}$$ then how many main scale divisions are there in $$1 \mathrm{~cm}$$ ?
5
40
10
20
Explanation
$$\begin{aligned}
& 0.04=4(\text { L. C.) } \\
& \Rightarrow \text { L.C }=0.01 \mathrm{~mm} \\
& \begin{array}{l}
1 \mathrm{MSD}-\frac{49}{50} M S D=0.01 \mathrm{~mm} \\
\Rightarrow 1 \mathrm{MSD}=50 \times 0.01 \mathrm{~mm} \\
\quad=0.5 \mathrm{~mm} \\
\Rightarrow 1 \mathrm{~cm}=20(0.5 \mathrm{~mm})
\end{array}
\end{aligned}$$
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