A non-inductive resistor is connected in series with a
coil across a 230 V, 50 Hz supply. The current is 1.8 A
and the potential differences across the resistor and
the coil are 80 V and 170 V respectively. Calculate the
inductance and the resistance of the coil, and the phase
difference between the current and the supply voltage.
Also draw the phasor diagram representing the current and the voltages.
1 answer
wikipedia's fine article on RL circuits has all the formulas and discussions you should need for this problem.