One main scale division of a vernier callipers is a cm and n ^ th division of the vernier scale coincide with (n - 1) ^ th division of the main scale. The least count of the callipers in mm is :

Correct answer: D. (10a)/(n) (n - 1)a = n( a ^ ' ) a ^ ' = ((n - 1)a)/(n) ∴ L . C . = 1MSD - 1VSD = (a - a ^ ' )cm = a - ((n - 1)a)/(n) = (na - na + a)/(n) = (a)/(n)cm = ((10a)/(n))mm

JEE Main 202116 MarchMorning Shift

Exam: JEE Main
Year: 2021
Date: 16 March
Shift: Morning Shift
Subject: Physics
Chapter: Experimental Physics

JEE Main 2021 · 16 March · Morning Shift · Physics · Experimental Physics

One main scale division of a vernier callipers is a cm and n ^ th...

One main scale division of a vernier callipers is

a

cm

and

{n}^{th}

division of the vernier scale coincide with

{\left(n - 1\right)}

^{th}

division of the main scale. The least count of the callipers in

mm is :

Options

A\dfrac{10na}{ $\left(n - 1\right)}$
B\dfrac{10a}{ $\left(n - 1\right)}$
C\dfrac{ $\left(n - 1\right)}{10n}$
D $\dfrac{10a}{n}$

Correct answer

D. $\dfrac{10a}{n}$

Step-by-step solution

$\left(n - 1\right)a = n\left({a}^{'}\right)$

${a}^{'} = \dfrac{\left(n - 1\right)a}{n}$

$∴ L . C . = 1MSD - 1VSD$

$= \left(a - {a}^{'}\right)cm$

$= a - \dfrac{\left(n - 1\right)a}{n}$

$= \dfrac{na - na + a}{n} = \dfrac{a}{n}cm$

$= \left(\dfrac{10a}{n}\right)mm$

Practice Experimental Physics on Quantrex Academy →

More from Experimental Physics

Two thin wires, Wire-1 of diameter 0.650 mm and Wire-2 of unknown diameter d are given.… JEE Advanced 2026 In a Vernier calipers, when both jaws touch each other, zero of the Vernier scale is… JEE Main 2026 In a screw gauge when the circular scale is given five complete rotations it moves… JEE Main 2026 In a screw gauge the zero of main scale reference line coincides with the fifth division… JEE Main 2026 In an experiment, a set of reading are obtained as follows - 1.24 ~mm, 1.25 ~mm, 1.23 ~mm… JEE Main 2026 When both jaws of vernier callipers touch each other, zero mark of the vernier scale is… JEE Main 2026 In a vernier callipers, 50 vernier scale divisions are equal to 48 main scale divisions.… JEE Main 2026 In a screw gauge, the zero of the circular scale lies 3 divisions above the horizontal… JEE Main 2026 Full Experimental Physics list All JEE Main PYQs