Question

Consider the following data for a vernier calliper:
10 main scale division = 1 cm.
10 vernier division matches with 9 Main scale division.

While measuring the zero error of the vernier we see that zero of vernier scale is to the right of the zero marking of the main scale with $6^{th}$ vernier division coinciding with main scale divisions.

The actual reading for length measurement is 4.3 cm with 2nd vernier division coinciding with main scale graduation.

Estimate the length.

• A. 4.32 $cm$
• B. 4.38 $cm$
• C. 4.26 $cm$
• D. 4.36 $cm$

Answer 1

The correct option is C

4.26 $cm$

$10MSD=1cm$
$\therefore 1MSD=0.1cm=1mm$

Also, $10VSD=9MSD$
$\therefore 1VSD=0.9MSD$
$1VSD=0.9mm$

Least count of vernier Calliper is:
$L.C.=1MSD-1VSD$
$L.C.=1mm-0.9mm$
$L.C.=0.1mm$

Also given while measuring the zero error, zero of vernier is to the right of the main scale. So, zero error is:
$Z=+6LC$
$Z=6\times 0.1mm=0.6mm$

Actual reading,
$MR=MSR+VSR-Z$
$MR=43+(2\times 0.1)-0.6mm$
$MR=4.26cm$