AC Fundamentals, Circuit and Circuit Theory
The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of

Increase in temperature
Capacitive effect between adjacent coil turns
Iron loss in core
Skin effect

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AC Fundamentals, Circuit and Circuit Theory
Pure inductive circuit

Consumes some power on average
None of the listed here
Does not take power at all from a line
Takes power from the line during some part of the cycle and then returns back to it during other part of the cycle

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AC Fundamentals, Circuit and Circuit Theory
In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value

Will change the resonance frequency
Will change the impedance at resonance frequency
Will change the maximum value of current at resonance
Will increase the selectivity of the circuit

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