A parallel-plate capacitor has separation 5d. A conducting slab of thickness d occupies x=d to 2d, and a dielectric slab of thickness d occupies x=3d to 4d as shown. Which graph of potential V versus x is correct?
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Question

A parallel-plate capacitor has separation 5d. A conducting slab of thickness d occupies x=d to 2d, and a dielectric slab of thickness d occupies x=3d to 4d as shown. Which graph of potential V versus x is correct?

Options

G1 Physics · Accepted Answer

Potential is constant through the conducting slab because E=0. It varies linearly in each homogeneous non-conducting region, with smaller slope in the dielectric than in air. The only graph with these features is Image 2. Correct answer: B.