A capacitor is connected across an ac source that has voltage amplitude 58.0 V and frequency 75.5 Hz.
Part A: What is the phase angle for the source voltage relative to the current?
Part B: Does the source voltage lag or lead the current?
Part C: What is the capacitance C of the capacitor if the current amplitude is 5.55 A?
2 Answers

A) 90 degrees
B) lag
C) V=IZ Z= j/wC
V=I ( j/wC)
c= I/Vw
C= 5.55/( 58 x 2 x pi x 75.5)
a way to remember the phase difference in capacitors and inductors is the phrase : ELI the ICE man
E(voltage) L(inductor) I(current ) voltage is before current (leads current in an inductor)
I(current) C(capacitance) E(voltage ) current is before voltage (leads voltage in a capacitor

a,b) If the series resistance in the circuit is negligeable, the voltage lags the current by 90deg.
c) I = VB = VC2pi*f where B is the susceptance of the cap (reciprocal of reactance; B = 1/X)
C = I/(V*2*pi*f) = 302.7uF