Why Does Adding a Choke Dim an Electric Lamp in an AC Circuit?

AI Thread Summary
Adding a choke in series with an electric lamp in an AC circuit reduces the current due to increased impedance, resulting in a dimmed lamp. The relationship between voltage, resistance, and inductive reactance shows that the current decreases when a choke is introduced. When a variable capacitor is added, it can be adjusted to counteract the inductive reactance of the choke. If the reactance of the capacitor equals that of the choke, the overall impedance returns to the resistance level, allowing the lamp to glow at normal brightness. This explanation accurately describes the effects of inductive and capacitive components on lamp brightness in an AC circuit.
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A)) A choke boil placed in series with an electric lamp in an AC circuit causes the lamp to become dim. Why?
B)) A variable capacitor "added" in this circuit maybe adjusted until the lamp glows with normal brilliance. Explain how this is possible

ATTEMPT:
If V is the voltage of alternating source, and I is the current flowing when no inductor or capacitor is connected, then
I 1=V/R
If now a choke of inductive reactance Xl is placed in series with the electric lamp, the new impedance of the circuit will be
Z 1=underroot<Rsquare + Xlsquare>
Therefore current flowing will be
I 2=V/[underroot<Rsquare + Xlsquare>]
From the comparison of equations of current, we see that I 2 < I 1 and that is why the electric lamp is dimmed on placing a choke in the circuit.
When a variable capacitor is added in series, Xc opposes Xl and thus
Z 2=underroot<Rsquare + (Xlsquare-Xcsquare)>
Therefore,
I 3=V/[underroot<Rsquare + (Xlsquare-Xcsquare)>]
If Xl = Xc, then Z 2=R
And current becomes equal to I 1 as if there's no reactance in the circuit and hence the lamp glows with normal brilliance.

Can you check whether this is a correct explanation?
 
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Yes. Your explanation is correct.
 
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