A parallel-plate capacitor has a dielectric slab of dielectric constant K covering one-third of the plate area, as shown. The total capacitance is C and the capacitance of the dielectric-covered portion is C₁. When charged, charges Q₁ and Q₂ appear on the dielectric-covered and air-filled portions respectively. Choose the correct option(s), ignoring edge effects.

Question

G1 Physics · Accepted Answer

The air-filled and dielectric-filled portions are in parallel, so both have the same potential difference and E₁=E₂. Also C₁=(Kε₀A/3d) and C=(ε₀A/3d)(K+2), hence C/C₁=(K+2)/K. Thus A,D.