1)A coil of self inductance of 0.7 Henry is joined in series with a non inductive resistance of 5 ohms. Calculate the wattless and power components as well as total current when connected to a supply of 200 volts at frequency of 50 cycles per second.
The Attempt at a Solution
It is given in my book that the power component of current = I(1)[cos(theta)]
Where I(1) = Root Mean Square value of total current in the circuit
I think theta is the phase difference between current and voltage in circuit
Also they say that the wattless component of current = I(1)[sin(theta)]
Could somebody please explain, what is the concept behind this?