Given : R=40Ω , L= 20 mH , C=50 μF
Comparing the given equation for voltage with general equation V=V0sinωt
ω=340rads−1 and peak voltage V0=10V
Inductive reactance XLωL=340×20×10−3=68×10−1=6.8Ω
Capacitive reactance XC
ωC1=340×50×10−61=34×5104=342×103
=0.0588×103=58.82Ω
Z=(XL−XC)2+R2⇒Z=(ωL−ωC1)2+R2
Z=(58.8−6.8)2+(40)2 ⇒ Z=2704+1600≈65.6Ω
Irms=ZVrms=65.6×210(Vrms=2V0)
Power =ErmsIrmscosϕ=Irms2R
(∵cosϕ=ZR,Vrms=IrmsZ)
=(65.6)2×2100×40=(65.6)22000
=0.51W