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). Which of the following graphs best represents the resulting curve

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

 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 increase 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, so option be is best suitable.