Question

if a capacitor is connected across an AC source. If a dielectric slab is inserted between the plates then what happens to current​

Answer 1

Explanation:

When a dielectric is placed in an electric field then an internal electric field is produced in it due to polarisation of dielectric . This internal electric field inside the dielectric is in opposite direction of the field between plates of capacitor , as a result of this effective electric field between plates decreases , hence the potential difference between plates because ,

E=ΔV/Δr ,

where Δr is the distance between plates , which is constant .

Now potential energy of a capacitor is given by ,

U=(1/2)qΔV ,

charge is given constant , therefore due to decrease in potential difference ΔV , potential energy U also decreases .

Answer 2

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Explanation:

When a dielectric is placed in an electric field then an internal electric field is produced in it due to polarisation of dielectric . This internal electric field inside the dielectric is in opposite direction of the field between plates of capacitor , as a result of this effective electric field between plates decreases , hence the potential difference between plates because ,

E=ΔV/Δr ,

where Δr is the distance between plates , which is constant .

Now potential energy of a capacitor is given by ,

U=(1/2)qΔV ,

charge is given constant , therefore due to decrease in potential difference ΔV , potential energy U also decreases .

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