Question

An inductor coil is connected to a capacitor and an $AC$ source of rms voltage $8\, V$ in series. The rms current in the circuit is $16 \,A$ and is in phase with emf. If this inductor coil is connected to $6\, V\, DC$ battery, the magnitude of steady current is

• A. 8 A
• B. 10 A
• C. 12 A
• D. 16 A

Answer 1

Answer: (C)

Given,
$rms$ voltage of $AC$ source $V_{ rms }=8 V$ and the $rms$
current in the circuit, $I_{ rms }=16\, A$
According to the question,

$\therefore $ Impedance of the circuit,
$Z=\frac{V_{ rmS }}{I_{ rms }}=\frac{8}{16}$
$Z=0.5 \,\Omega$
When the inductor coil is connected to a $6 \,V\,DC$
battery then $V_{ rms }^{'}=6\, V =V_{D C}$
$\therefore $ Magnitude of steady current,
$I^{'}=\frac{V_{ rms }^{'}}{Z}=\frac{6}{0.5}=12\, A$