JEE Mains · Physics · STD 11 - 1. units,dimensions and measurement
A student measured the length of a rod and wrote it as \(3.50\;cm\). Which instrument did he use to measure it?
- A A vernier calliper where the \(10\) divisions in vernier scale matches with \(9\) division in main scale and main scale has \(10\) divisions in \(1\; cm\).
- B A screw gauge having \(100\) divisions in the circular scale and pitch as \(1\; mm.\)
- C A screw gauge having \(50\) divisions in the circular scale and pitch as \(1\; mm.\)
- D A meter scale.
Answer & Solution
Correct Answer
(A) A vernier calliper where the \(10\) divisions in vernier scale matches with \(9\) division in main scale and main scale has \(10\) divisions in \(1\; cm\).
Step-by-step Solution
Detailed explanation
If student measures \(3.50 \mathrm{cm},\) it means that there is an uncertainly of order \(0.01 \mathrm{cm} .\) For vernier scale with \(1 \mathrm{MSD}=\frac{1}{10} \mathrm{cm}\) and \(9 \mathrm{MSD}=10 \mathrm{VSD}\) \(LC\) of vernier calliper \(=1 \mathrm{MSD}-1 \mathrm{VSD}\)…
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