Question

a resistor (R=750), a Capacitor (C=3.36uf) and inductor (L=2.34H) are connected in series across a 120Hz Ac source for which change in V=105V.

a) calculate rms voltage across the capacitor

b) calculate phase angle between the current and voltage

c) is the current leading or lagging the voltage

d) what is the average power delivered by the voltage source

Answer 1

first we will calculate the

Z=undrt(R^2+(XL-XC)^2)

XL=2*pie*f*L

=2*3.14*120*2.34

=1763.42

XC=1/2*pie*f*C

=1/2*3.14*120*3.36*10^-6

=0.000394*10^6

=394

Z=undr(R^2+(XL-XC)^2

=undrt(750^2+(1763.42-394)^2

Z=1561.3ohm

I=E/Z

=105/1561.3

I=0.067Amp

voltage across capacitor will be

Vc = I•Xc

=0.067*3.36*10^-6

Vc=0.225*10^-6V--answer to a

b)thetha = arc tan XL/R

thetha=arctan(1763.42/750)

=87 degrees--answer to b

c) The circuit Voltage leads the circuit current by 87 degrees.--answer to c

d)P=V^2/R

=105^2/750

=14.7 watt--answer to d