A step down transformer connected to an ac mains supply of 220 V is made to operate at 11 V, 44W lamp. Ignoring power losses in the transformer, what is the current in the primary circuit ?

A series LCR circuit containing 5.0 H inductor, 80$$\mu$$F capacitor and 40$$\Omega$$ resistor is connected to 230V variable frequency ac source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be :

A 40 $$\mu $$F capacitor is connected to a 200 V. 50 Hz ac supply. The rms value of the current on the circuit is, nearly :

A series LCR circuit is connected to an ac voltage source. When L is removed from the circuit, the phase difference between current and voltage is $${\pi \over 3}$$. If instead C is removed from the circuit, the phase difference is again $${\pi \over 3}$$ between current and voltage. The power factor of the circuit is :