A `100 Omega` resistor is connected to a 220 V, 50 Hz ac supply.
(a) What is the rms value of current in the circuit?
(b) What is the net power consumed over a full cycle?

Explanation

(i) `R_(rms)` value of current in the circuit.
`I_(rms) = (V_(rms))/R = (220)/100 = 2.2A`
(ii) We know that the power dissipated in an AC circuit is given by `P=V_(rms)I_(rms)cosphi`
Where, `phi` is the phase difference between current and voltage In a circuit containing resistor only, `phi-0^(@)`, thus `cosphi=cos0^(@)=1`
`therefore P=V_(rms).I_(rms)`
`=220 xx 2.2 = 484`W