The voltage across each branch of a parallel section of a circuit (branches connected between the same two junctions) will be the same. Kirchhoff's Voltage Law says that The sum of voltages around a loop is zero. The sum of e.m.f.s around a loop equals the sum of potential differences around the loop.This is a statement based on the law of conservation of energy.The potential difference from one junction in the circuit to another must always be the same.