At t = 0 , a charged particle is released in a uniform electric field at the given position. The electric field is produced by 2 charged plates on opposite sides of the screen, 20 cm apart. The electric field is represented by the green lines and the equipotentials by the gray lines. The direction of the electric force on the particle is indicated. Charge in units of e (1 e = 1.6E-19 C) is given as an input. Mass in units of u (1 u = 1.66E-27 kg) is given as an output. For easy visual identification, positive charges show as red and negative charges as blue. The potential difference may be reversed by making the potential of the left plate negative. This will also reverse the colors of the plates. The red plate is always at higher potential than the blue plate. The potential at the current position of the particle is shown as an output. The bar graphs in the yellow window show the electrical potential energy and the work done by the electric field on the particle as it moves.