[ SPM Physics Question ] How to solve this question?

The diagram below shows the scale of a vernier calliper to measure the diameter of a stell ball.
The zero error of the vernier calliper is +0.02 \mathrm{~cm}
What is the actual reading of the vernier calliper?
A. 3.30 \mathrm{~cm}
B. 3.32 \mathrm{~cm}
C. 3.34 \mathrm{~cm}
D. 3.40 \mathrm{~cm}

First step: Identify the first decimal point

From the figure above, we notice that the Vernier scale alignment of 0 with the main scale lies between 3 and 4, hence the reading should be somewhere at 3.3x cm.

Second step: Identify the EXACT alignment of Vernier scale with main scale:

Therefore, the exact reading should be 3.34 cm.

Third step: Account for Zero Error
HOWEVER, since there is a zero error of 0.02 cm, it must be deducted from the ‘exact’ reading.
Therefore, the true/actual reading is

3.34 - (+0.02) = 3.32 cm.

Answer is B. 3.32 cm

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Thank you very much!:blush::blush::+1::+1: