Alternating current (AC) in an electrical circuit can be described by complex numbers. In any electrical circuit, Z, the impedance in the circuit, is related to the voltage V and the current I by the formula Z = V/I. The standard electrical voltage in Europe is 220 volts, so in these problems use V = 220.

a. Find the impedance in a standard European circuit if the current is 22 – 11i amps.
b. Find the current in a standard European circuit if the impedance is 10 – 5i watts.
c. Find the impedance in a standard European circuit if the current is 20i amps