RL Circuits - Engineering

Q1:

A 47  resistor is in series with an inductive reactance of 120  across an ac source. The impedance, expressed in polar form, is

A 4768.6° 

B 12068.6° 

C 12931.4° 

D 12968.6° 

ANS:D - 12968.6° 

Z= R+jXL.
= (47^2+120^2)1^1/2.
= 128.87.
= tan^-1(XL/R)=68.8.