A check coil in series with a lamp is connected to a d.c line. The lamp is seen to shine brightly and insertion of an iron core in the choke causes no change in the lamps brightness. Predict the corresponding observation if the connection is to as a.c line

Question

$\begin{array}{1 1} \text{The brightness of the bulb increases} \\ \text{The brightness of the bulb decreases} \\ \text{The brightness of the bulb first increases and then decreases} \\ \text{The brightness of the bulb first decreases and then increases} \\ \end{array}$