A solenoid and a bulb are connected with a ac source . How will the brightness of bulb change if an iron core is inserted in the solenoid?

Answers (1)
A Avinash Dongre

As iron is inserted, the magnetic field inside of the solenoid coil  increases. hence, the its inductive reactance increases.

        As X_{L}=L\omega

for inductor, I is equal to  I=\frac{V}{ L\omega }

therefore, current decreases as increase in L and hence brightness of bulb decreases.