Suppose the frequency of the source in the previous example can be varied. (a) What is the frequency of the source at which resonance occurs? (b) Calculate the impedance, the current, and the power dissipated at the resonant condition.

Explanation

At resonance, `|Z|=` minimum
`= R = 3 Omega`
Power dissipated at resonance is
`P = I_(rms) ^(2) R`
`= { ( V_(rms))/( |Z| ) }^(2) R`
`= { ( V_(rms))/( R ) }^(2) R` ( At resonance, `|Z| = R )`
`= ( V_(rms)^(2))/( R)`
`= (((V_(m))/(sqrt(2)))^(2))/(R )`
`= ( V_(m)^(2))/( 2R)`
`:. P = (( 283)^(2))/( 2 xx 3 )`
`:. P = 13348 W` (Watt )
Above is the maximum power fetched by the circuit from the source and the same is wasted in the form of heat in the resistance ( at the time of resonance ).