A metal sphere with 1 m radius and a surface charge density of 10 Coulombs/m² is enclosed in a cube of 10 m side. The total outward electric displacement normal to the surface of the cube is

The electric field strength at a distance point, P, due to a point charge, +q, located at the origin, is 100 $$\mu $$V/m. If the point charge is now enclosed by a perfectly conducting metal sheet sphere whose center is at the origin, then the electric field strength at the point P outside the sphere becomes.

In the infinite plane, y = 6 m, there exists a uniform surface charge density of (1/6000$$\pi $$) $$\mu $$C/m². The associated electric field strength is: