Here are the essential concepts you must grasp in order to answer the question correctly.
Accuracy
Accuracy refers to how close a measured value is to the true or accepted value. In this context, the true pH of the rainwater is known to be 5.12, so an accurate measurement would be one that is close to this value. If the uncalibrated pH meter consistently gives readings that differ significantly from 5.12, it would be considered inaccurate.
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Precision
Precision indicates the consistency or repeatability of measurements, regardless of their accuracy. If the uncalibrated pH meter provides similar readings across multiple measurements, it is considered precise. However, if those readings are widely spread out or vary significantly, the meter lacks precision, even if some readings might coincidentally be close to the true value.
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Significant Figures Precision
Calibration
Calibration is the process of adjusting an instrument to ensure its measurements are accurate. A calibrated pH meter uses known pH solutions to set its scale, allowing it to provide reliable readings. In contrast, an uncalibrated pH meter may yield results that are systematically off from the true value, affecting both its accuracy and precision.
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