An ac voltage source is connected in series with a 1.5 mF capacitor and a 750 Ω resistor. Using a digital ac voltmeter, the amplitude of the voltage source is measured to be 4 Volt rms, while the voltages across the resistor and across the capacitor are found to be 3 Volt rms and 2.7 Volt rms, correspondingly.
a) Obtain the frequency of the ac voltage source.