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 __________ $\mathrm{cm}$.
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 $=8.5+0.06-0.02=8.54 \mathrm{~cm}$