The two ends of a uniform conductor are joined to a cell of e.m. f . E and some internal resistance. Starting from the midpoint P of the conductor, we move in the direction of current and return to P The potential V at every point on the path is plotted against the distance covered (x). Whichof the following graphs best represents the resulting curve?

When we move in the direction of the current in a uniform conductor, the potential difference decreases linearly. When we pass through the cell, from its negative to its positive terminal, the potential increases by an amount equal to its potential difference. This is less than its emf, as there is some potential drop across its internal resistance when the cell is driving current.