Question

There are two Vernier calipers both of which have $1cm$ divided into $10$ equal divisions on the main scale. The Vernier scale of one of the calipers ($C_1$) has $10$ equal divisions that correspond to $9$ main scale divisions. The Vernier scale of the other caliper ($C_2$) has $10$ equal divisions that corresponds to $11$ main scale divisions. The readings of the two calipers are shown in the figure. The measured values (in $cm$) by calipers $C_1$ and $C_2$, respectively, are
:

• A. $2.87$ and $2.87$
• B. $2.87$ and $2.83$
• C. $2.85$ and $2.82$
• D. $2.87$ and $2.86$

Answer 1

The correct option is B $2.87$ and $2.83$

$MSD=\frac{1}{10}cm$ = $0.1cm$
For first vernier caliper, $10VSD=9MSD$
⇒ $VSD=\frac{9}{10}MSD$ = $0.9\times 0.1=0.09cm$

Reading;
= main scale reading upto coinciding main scale division − $n\times VSD$
= $3.5-7\times 0.09$ $\Rightarrow 3.5–0.63=2.87cm$

For second vernier caliper, $10VSD=11MSD$
⇒ $VSD=\frac{11}{10}MSD=1.1\times 0.1=0.11cm$
Reading =$3.6-7\times 0.11=3.6–0.77=2.83cm$