When a gauge reads 25 psi, what is the calculated accuracy percentage based on ±0.6 psi?

• A. 2.0%
• B. 2.2%
• C. 2.4%
• D. 2.6%

Answer: (C)

To determine the accuracy percentage of the gauge reading, you need to understand how accuracy is calculated relative to the reading and the uncertainty. The formula for calculating the accuracy percentage is as follows:

Accuracy (%) = (Uncertainty / Reading) x 100

In this case, the reading is 25 psi, and the uncertainty (or tolerance) is ±0.6 psi. First, you would compute the accuracy with the given values.

Calculate the accuracy percentage:

1. Divide the uncertainty by the reading:

0.6 psi / 25 psi = 0.024

2. Convert this decimal to a percentage by multiplying by 100:

0.024 x 100 = 2.4%

This means that the gauge has an accuracy of 2.4% at a reading of 25 psi.

Choosing the answer based on this calculation, the correct accuracy percentage is indeed 2.4%, which aligns with option C. This process demonstrates the relationship between the gauge reading and the associated uncertainty, illustrating the importance of understanding how to interpret instrument readings accurately in the context of process control.