A charged particle's trajectory inside a region with uniform electric and magnetic fields is investigated. Analytical solution is obtained.

Suppose you form an off-centered spherical cavity inside a charged insulating sphere. Can you find the electric field inside this cavity?

An n-sided regular polygon possesses a positive charge q at each of its vertices. Find the net electric field at the center.

Stable and/or Unstable equilibrium points for a three electric charge system is investigated. Frequency of oscillations is determined.