A travelling microscope has 20 divisions per cm on main scale while its Vernier scale has total 50 d

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1.Units, Dimensions and Measurement

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A travelling microscope has $20$ divisions per $cm$ on the main scale while its Vernier scale has total $50$ divisions and $25$ Vernier scale divisions are equal to $24$ main scale divisions, what is the least count of the travelling microscope $..........\,cm$

A

$0.001$

B

$0.0002$

C

$0.002$

D

$0.005$

(JEE MAIN-2022)

Solution

$1\,MSD =\frac{1}{20}\,cm$

$1\,VSD =\frac{24}{25}\,MSD =\frac{24}{25} \times \frac{1}{20}\,cm$

$\therefore$ Least count $=\frac{1}{20}\left(1-\frac{24}{25}\right)\,cm$

$=\frac{1}{20} \times \frac{1}{25}=\frac{1}{500}\,cm$

$=0.002\,cm$

Standard 11

Physics

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