Charge is distributed with uniform surface charge density sigma on a circular disc with radius a. the disc lies in the xy plane with center at the origin. find the electric field at a point (o, o, z) on the z-axis. explicitly calculate the limiting forms of the solution at very small (z < < a) and at very large (z > > a) z compared to a.

The space within which a test north pole experiences a force magnetic poles 2. a powerful stream of electrons flowing high above the earth in the ionosphere electrojet 3. a concept to explain the directional nature of a magnetic field field lines 4. coil of wire designed to produce a magnetic field by a current passing through its windings ionosphere 5. that region above the earth's atmosphere where particles exist in an ionized state magnetic field 6. the extremities of a magnet where the field lines tend to converge or concentrate aurora borealis 7. a phenomenon that occurs in the northern latitudes; the northern lights solenoid