Q1: What is the phase angle between the source voltage and current, when a 100 mH inductor with a reactance of 6 k, and a 1 k resistor are in series with a source?

ANS:D - 81.0 degrees

tan θ = (XC/R) ==> θ = tan^(-1) (XC/R) ==> (Phase angle for SERIES RC Circuit)
tan θ = (R/XC) ==> θ = tan^(-1) (R/XC) ==> (Phase angle for PARALLEL RC Circuit)

tan θ = (XL/R) ==> θ = tan^(-1) (XL/R) ==>(Phase angle for SERIES RL Circuit)
tan θ = (R/XL) ==> θ = tan^(-1) (R/XL)) ==> (Phase angle for PARALLEL RL Circuit)

Given: L = 100 m H; XL = 6 kΩ, R = 1 k Ω, θ =?

tan θ = (XL/R) = θ = tan^(-1) (XL/R) ==>(Phase angle for SERIES RL Circuit)
tan θ = (XL/R) = θ = tan^(-1) (6 kΩ /1 kΩ) ==> tan^(-1) (6) = 80.53 -> 81.00 °.