$4.$ A $50$ kHz sinusoidal voltage has zero phase angle and a maximum amplitude of $10$ mV$.$ When

this voltage is applied across the terminals of a capacitor, the resulting steady$-$state current has

a maximum amplitude of $628\mathrm{.}32$ A$.$

a$)$ What is the phase angle of the current?

b$)$ What is the capacitive reactance of the capacitor?

c$)$ What is the capacitance of the capacitor, in microfarads?

d$)$ What is the impedance of the capacitor?

Answer: a$)314,159\mathrm{.}27$ rad$/$s; b$)90$; c$)15\mathrm{.}92$; d$)0\mathrm{.}2$ F; e$)$j$15\mathrm{.}92.$