試題詳解

5. A nonuniform electric field is directed along the x-axis at all points in space. This magnitude of the field varies with x, but not with respect to y or z. The axis of a cylindrical surface, 0.80 m long and 0.20 m in diameter, is aligned parallel to the x-axis, as shown in the figure. The electric fields E₁ and E₂, at the ends of the cylindrical surface, have magnitudes of 9000 N/C and 5000 N/C respectively, and are directed as shown. (ε = 8.85 x 10^-12 C²/N ㆍm²) The charge enclosed by the cylindrical surface is closes
(A) -2.4 nC.
(B) -4.8 nC.
(C)-1.1 nC.
(D)4.8 nC.
(E) 1.1 nc.