Homework Help: Electromagnetic Induction in AC circuits

1. Mar 31, 2010

Cal66

A 9.7 Ω resistor, a 10.8 µF capacitor, and a 27.9 mH inductor are connected in series with a 120 V (rms) source with variable frequency.
(a) At what frequency will the current be maximum?

Hz

(b) Find the maximum rms current.

A

(c) Suppose you now replace the 10.8 µF capacitor by a 22.0 µF capacitor. What is the new value of the rms current?

A

a ) frequency f = 1 / 2π √ L C
= 1/ 2π √27.9 mH * 10.8μF
= _____ Hz cannot get right frequency
b ) Maximum rms current Irms = Vrms / XC
XC = 1/ 2π f C
= 1/ 2π * f Hz * 10.8μF
= _____ Ω
Irms = 120 V / XC Ω
= ____
c ) Maximum rms current Irms = Vrms / XC
XC = 1/ 2π f C
= 1/ 2π * f Hz * 22.0μF
= ___ Ω
Irms = 120 V / XC Ω