JEE Mains · Physics · STD 11 - Units,dimensions and measurement
- JEE Mains 2024
- Hard
- MCQ
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 \(1 \mathrm{~cm}\) ?
Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(20\)
Step-by-step Solution
Detailed explanation
\(4^{\text {th }}\) division coincides with \(3^{\text {rd }}\) division then
\( 0.004 \mathrm{~cm}=4 \mathrm{VSD}-3 \mathrm{MSD}\)
\(49 \mathrm{MSD}=50 \mathrm{VSD}\)
\(1 \mathrm{MSD}=\frac{1}{\mathrm{~N}} \mathrm{~cm}\)
\(0.004=4\left\{\frac{49}{50} \mathrm{MSD}\right\}-3 \mathrm{MSD}\)
\(0.004=\left(\frac{196}{50}-3\right)\left(\frac{1}{\mathrm{~N}}\right)\)
\(\mathrm{N}=\frac{46}{50} \times \frac{1000}{4}=\frac{46 \times 1000}{200}=230\)
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