Answer:
The pH meter has a scale on the screen that measures the pH value from 0 to 14 for a given solution. It works on the principle of comparing voltages reading. When the electrode is dipped into the solution, the voltage produced by the ions of the solution is send to pH meter that compares the reading to the known voltage value of a standard solution. The reading is then displayed on the meter. The measures of precise Potential Difference values plays an important role in pH measurements.