Fig shows a light bulb (B) and iron cored inductor connected to a DC battery through a switch (S).
i) What will one observe when switch (S) is closed?
ii) How will the glow of the bulb change when the battery is replaced by an ac source of rms voltage equal to the voltage of DC battery? Justify your answer in each case.


An electric lamp having coil of negligible inductance connected in series with a Capacitor and an AC source is glowing with certain brightness. How does the brightness of the lamp change on reducing the (i) capacitance, and (ii) the frequency of ac voltage?

Dear student

a when the switch S is closed, the bulb will give full brightness slowly, because inductor opposesthe rise of current in the circuit depending on the value of the ratio LR, where L=inductance and R= resistance of the bulb.bWhen battery is replaced by an ac source of rms voltage equal to the dc voltage of battery, the inductor offers reactance XL=ωL, so the impedance of circuit increases and the bulb will glow with less brightness.

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