The magnitude of three-phase fault currents at buses A and B of a power system are \(10\;pu\) and \(8\;pu\), respectively. Neglect all resistances in the system and consider the pre-fault system to be unloaded. The pre-fault voltage at all buses in the system \(1.0\;pu\) is . The voltage magnitude at bus B during a three-phase fault at bus A is \(0.8\;pu\). The voltage magnitude at bus A during a three-phase fault at bus B, in \(pu\), is ________.