Q.

Two parallel plate capacitors C1 and C2, each having capacitance of 10μF, are individually charged by a 100 V D.C. source. Capacitor C1 is kept connected to the source and a dielectric slab is inserted between its plates. Capacitor C2 is disconnected from the source and then a dielectric slab is inserted in it. Afterwards, the capacitor C1 is also disconnected from the source and the two capacitors are finally connected in parallel combination. The common potential of the combination will be ____ V.  (Assuming dielectric constant =10)                     [2023]


Ans.

(55)

Charge on C1=KCE

and charge on C2=CE

When they are connected in parallel, charge will be equally divided, so charge on one capacitor is

           q=K+12CV

So   V=qKC=K+12K=55 V