Change in the Brightness of the bulb in cases (i), (ii) & (iii) Justification(i) Increases $X_L=\omega L$ As number of turns decreases, $L$ decreases, hence current through bulb increases. / Voltage across bulb increases.(ii) DecreasesIron rod increases the inductance which increases $X_L$ , hence current through the bulb decreases./ Voltage across bulb decreases.(iii) IncreasesUnder this condition $(X_C=X_L)$ the current through the bulb will become maximum / increase.