In Ohm's Law, voltage is represented by the letter __ in all the math formulas.

In Ohm's Law, voltage is represented with the letter "V." The formula that expresses this relationship is V = I * R, where V is voltage, I is current, and R is resistance.

In this context, it’s essential to note why "V" is the correct representation of voltage. Using "E" for voltage is more common in certain electrical engineering texts, where "E" denotes electromotive force (also referred to as voltage), however, in the most widely recognized applications of Ohm's Law, voltage is typically labeled as "V." The use of "V" provides a standardization in calculations involving electrical circuits and reinforces a clear understanding of the fundamental electrical parameters.

The other options represent different physical quantities: "P" stands for power, "I" represents current, and the meanings can vary slightly depending on the context. Using these letters in place of "V" would lead to confusion and inaccuracies when applying Ohm's Law in practical situations.