The power factor of a RC circuit is 12√. If the frequency of AC signal is halved, then the power factor of the circuit becomes:

The question seems to be incomplete. The power factor of an RC circuit is not typically represented as "12√". The power factor is a dimensionless number between 0 and 1. In an RC circuit, the power factor is determined by the phase difference between the voltage and the current. When the frequency of the AC signal is halved, the reactance of the capacitor changes, which in turn affects the phase difference and the power factor. However, without more specific information, it's not possible to provide a numerical answer to this question.