Question

What happens to brightness of lamp when iron rod inserted in inducttoe?

Answer 1

as iron is inserted, the magnetic field inside of the coil increases. hence, the inductive reactance increases. ... A bulb and a coil are connected in parallel, the combination is fed with a constant AC supply and the bulb glows with some brightness.

Answer 2

The brightness of the lamp decreases because when an iron rod is inserted in the inductor, the value of inductance L increases. Therefore, the current flowing across the bulb will decrease, thus decreasing the brightness of the bulb.