Physics Question from JEE Main 2023 · 31 January, Shift 2

Two parallel plate capacitors $C_1$ and $C_2$, each having capacitance of $10 \, \mu \text{F}$ are individually charged by a $100 \, \text{V}$ D.C. source. Capacitor $C_1$ is kept connected to the source and a dielectric slab is inserted between its plates. Capacitor $C_2$ is disconnected from the source and then a dielectric slab is inserted in it. Afterwards, the capacitor $C_1$ 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 = $10$)