An alternating emf source with a variable frequency fd is connected in series with an 80.0 B resistor and a 40.0 mH inductor. The emf amplitude is 6.00 V. (a) Draw a phasor diagram for phasor VR (the potential across the resistor) and phasor VL (the potential across the inductor). (b) At what driving frequency fd do the two phasors have the same length? At that driving frequency, what are (c) the phase angle in degrees, (d) the angular speed at which the phasors rotate, and (e) the current amplitude?