The vernier scale
Question:

The vernier scale used for measurement has a positive zero error of $0.2 \mathrm{~mm}$. If while taking a measurement it was noted that ‘ 0 ‘ on the vernier scale lies between $8.5 \mathrm{~cm}$ and $8.6 \mathrm{~cm}$, vernier coincidence is 6 , then the correct value of measurement is __________ $\mathrm{cm}$.

1. $8.36 \mathrm{~cm}$

2. $8.54 \mathrm{~cm}$

3. $8.58 \mathrm{~cm}$

4. $8.56 \mathrm{~cm}$

Correct Option: , 2

Solution:

Positive zero error $=0.2 \mathrm{~mm}$

Main scale reading $=8.5 \mathrm{~cm}$

Vernier scale reading $=6 \times 0.01=0.06 \mathrm{~cm}$

Final reading $=8.5+0.06-0.02=8.54 \mathrm{~cm}$