A parallel-plate capacitor is charged from a cell and then isolated. Dielectric K is inserted over the upper half of the plate area and dielectric 2K over the lower half. Let the electric fields be E₁ and E₂. Which statement is correct?
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Question

A parallel-plate capacitor is charged from a cell and then isolated. Dielectric K is inserted over the upper half of the plate area and dielectric 2K over the lower half. Let the electric fields be E₁ and E₂. Which statement is correct?

Select all that apply

G1 Physics · Accepted Answer

The two dielectric-filled regions are in parallel between the same plates, so they have the same voltage and same separation, hence E₁=E₂. Energy density is ½Kε₀E²; the 2K region stores twice the energy of the K region for equal area, so upper-half energy is less. Polarization charge and free-charge distribution are not equal. Correct answer: B.