Question
Assertion : A bulb connected in series with a solenoid is connected to ac source. If a soft iron core is introduced in the solenoid, the bulb will glow brighter.
Reason : On introducing soft iron core in the solenoid, the inductance increases.

Answer

(e) On introducing soft iron core, the bulb will glow dimmer. This is because on introducing soft iron core in the solenoid, its inductance $L$ increases, the inductive reactance, $X_L=\omega L$ increases and hence the current through the bulb decreases.

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