In a potentiometer circuit, the potential at point T is equal to E2 when the galvanometer reading is zero, regardless of the value of E1. The discussion clarifies that E2 is not directly connected to T due to the resistive wire lengths XT and TY, which introduce potential differences. To find the potential difference per unit length of the wire XY, one can use the formula E2 divided by the length XT. Understanding these relationships is crucial for solving the problem effectively. The key takeaway is that the potential difference per unit length can be determined without needing E1, as long as E2 is known.
