<p>A light bulb and an open coil inductor are connected to an a.c. source through a key as shown in Fig. 7.62.</p>

<p><img alt="" src="https://school.achievam.com/upload/questionbank/question/que_1758958622.PNG" style="height:178px; width:228px" />​​​​​​​</p>

<p>The switch is closed and after some time, an iron rod is inserted into the interior of the inductor. The glow of the light bulb : (a) increases; (b) decreases; (c) is unchanged, as the iron rod is inserted. Give your answer with reasons. What will be your answer it ac source is replaced by d.c. ?</p>