06 真空中的静电场_库仑定律习题.pdf

1 真空中的静电场 库仑定律习题 求电偶极子延长线和中垂线上的电场 求电偶极子延长线和中垂线上的电场 求电偶极子延长线和中垂线上的电场 求电偶极子延长线和中垂线上的电场 Find the field E E due to the dipoledipole of Fig at point p1 a distance y from the midpoint of the dipole on its central axis and at point p2 a distance x along the perpendicularperpendicular bisector bisector 中垂线中垂线中垂线中垂线 of the line joining the two charges 2 解 解 1 延长线 延长线P1 0 y 的电场强度 的电场强度 22 0 1 2 2 4 1 l y q l y q jEEE 2 中垂线 中垂线P2 x 0 的电场强度 的电场强度 23 2 2 0 2 2 2 2 0 2 4 1 4 4 2 4 4 2 l x i ql l x l l x q i EEE 3 当当 有 有 yandx 3 0 3 0 1 2 4 12 4 1 x P i x ql E 3 0 3 0 2 4 1 4 1 y P i y ql E Example The slender 细的 细的 rod of length l l carries q q Find the electric field at a point P with a distance a a from the center along the direction of rod P x 0 dx x 0dq 4 2 0 2 0 4 1 4 1 xx dx l q xx dq dE Solution 4 4 4 1 2 2 0 2 2 2 0 l x q xx dx l q E P l l P Example The slender 细的 细的 rod of charge with density What is the field E E at a distance a a from the line 0 1 2 a 5 Example 求均匀带电圆环轴线上任一点的场强 Fig shows a thin ring of radius R R charged to a constant linear charge density around its circumference Find the field at point P P a distance x x from the plane of the ring along its central axis a 0 x dl r P x dE dE dEx Example Example A ring with radius R carries charge in terms of Find electric field at point O x y R i i co