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**

Thank you very much!