An inductor-coil , a capacitor and an AC source of rms voltage `24 V` are connected in series. When the frequency of the source is varied, a maximum rms current of `6.0 A` is observed. If this inductor coil is connected to a battery of `emf 12 V` and internal resistance `4.0 Omega`, what will be the current?

Explanation

Maximum current will occur at series resonance
At series resonance `Z_(min) =R, i_(max) =6A`
`i_(max) = (V)/(Z)min implies 6= (24)/( R) `
`R =4Omega`
In dc circuit inductor offers zero resistance
`I = (12)/(4 +4) =1.5A`

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