A step-down transformer connected to an AC mains supply of \(220~\text{V}\) is made to operate at \(11~\text{V}\), \(44~\text{W}\) lamp. Ignoring power losses in the transformer, what is the current in the primary circuit?
1. \(2~\text{A}\)
2. \(4~\text{A}\)
3. \(0.2~\text{A}\)
4. \(0.4~\text{A}\)

A series LCR circuit containing \(5.0~\text{H}\) inductor, \(80~\mu \text{F}\) capacitor and \(40~\Omega\)$\mathrm{}$ resistor is connected to \(230~\text{V}\) 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:

An inductor of inductance \(L\), a capacitor of capacitance \(C\) and a resistor of resistance \(R\) are connected in series to an AC source of potential difference \(V\) volts as shown in Figure. The potential difference across \(L\), \(C\) and \(R\) is \(40~\text{V}\), \(10~\text{V}\) and \(40~\text{V}\), respectively. The amplitude of the current flowing through the \(LCR\) series circuit is \(10\sqrt{2}~\text{A}\). The impedance of the circuit will be:

      
1. \(4~\Omega\)
2. \(5~\Omega\)
3. \(4\sqrt{2}~\Omega\)
4. \(\frac{5}{\sqrt{2}}~\Omega\)

A light bulb and an inductor coil are connected to an AC source through a key as shown in the figure below. The key is closed and after some time an iron rod is inserted into the interior of the inductor. The glow of the light bulb:

An AC source given by \(V=V_m\sin\omega t\) is connected to a pure inductor \(L\) in a circuit and \(I_m\) is the peak value of the AC current. The instantaneous power supplied to the inductor is:
1.  \(\frac{V_mI_m}{2}\mathrm{sin}(2\omega t)\)
2.  \(-\frac{V_mI_m}{2}\mathrm{sin}(2\omega t)\)
3.  \({V_mI_m}\mathrm{sin}^{2}(\omega t)\)
4.  \(-{V_mI_m}\mathrm{sin}^{2}(\omega t)\)