12. A conducting spherical shell of inner radius a = 0.2 m and outer radius b = 0.25 m has a total charge of 5.0 μC on its surface. A point charge of -6.0 μC is placed at the center of the shell. Determine correct item for the electric field E in the regions: (A) a ＜ r , E = 1.0μC/(4πεor2) (B) a ＜ r ＜ b , E = 0 (C) r ＞ b , E = 6.0μC/(4πεor2) C/(4\pi\varepsilon_0 r^2) \)

14. Which following statement regarding the electric field or potential is correct? (A) The electric field at a short distance above a single plane, with uniform surface charge density σ, has the magnitude E =σ/ε0, where ε0 is permeability in air. (B) The electric field at any point between two parallel infinite conducting plates, each with uniform surface charge density σ, has the magnitude E =σ2/ε0. (C) The electric field at any point outside two parallel infinite conducting plates, each with uniform surface charge density σ, has the magnitude E = 0. (D) The electric potential at any point between two parallel infinite conducting plates, each with uniform surface charge density σ, has constant value.

相關試題

相關試卷