A capacitor is connected across an ac source that has voltage amplitude $50\mathrm{.}0$ VV and frequency $78\mathrm{.}0$ HzHz $.$ What is the phase angle $$ for the source voltage relative to the current? Does the source voltage lag or lead the current? What is the capacitance CC of the capacitor if the current amplitude is $5\mathrm{.}45$ AA $?$