NEET-XII-Physics
39: Alternating Current
- #6An AC source is connected to a capacitor. Will the rms current increase, decrease or remain constant if a dielectric slab is inserted into the capacitor?Ans : The reactance of a capacitor is given by,
`` {X}_{c}=\frac{1}{\omega C}``
Also,
`` C=\frac{K{\epsilon }_{0}A}{d}``,
where C = capacitance
K = dielectric constant
A = area of plates
d = distance between the plates.
`` K>1``
`` \therefore `` The capacitance C of the capacitor will increase on inserting the dielectric slab and, consequently, the reactance Xc will decrease.
Rms current, `` {i}_{rms}=\frac{{\epsilon }_{0}}{\sqrt{2}{X}_{C}}``
Therefore, rms current will decrease.
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