Two parallel plate capacitors C₁ and C₂ each of capacitance 10 μF are individually charged by a 100 V DC source. C₁ remains connected to source while a dielectric slab of dielectric constant 10 is inserted. C₂ is disconnected before inserting the same dielectric. Afterwards C₁ is also disconnected and the two capacitors are connected in parallel. The common potential is ______ V.
Physics · Circular Motion
JEE Mains 31 January 2023 Shift 2 Evening Shift

Question

Two parallel plate capacitors C₁ and C₂ each of capacitance 10 μF are individually charged by a 100 V DC source. C₁ remains connected to source while a dielectric slab of dielectric constant 10 is inserted. C₂ is disconnected before inserting the same dielectric. Afterwards C₁ is also disconnected and the two capacitors are connected in parallel. The common potential is ______ V.

Physics · Circular Motion

JEE Mains 31 January 2023 Shift 2 Evening Shift

G1 Physics · Accepted Answer

After dielectric insertion, each capacitance becomes 100 μF. For C₁, while connected to source, charge becomes Q₁=100 μF×100 V=10000 μC. For C₂, charge remains Q₂=10 μF×100 V=1000 μC. On parallel connection, total capacitance = 200 μF and total charge = 11000 μC. Common potential = 11000/200 = 55 V.