Stimulation link: compadre.org/Physlets/electromagnetism/prob23_1.cfm

IE| = +0.438 A fixed particle with an unknown charge is shown along with a dragable test charge. The vectors shown point in the direction of the electric field, and the color of the vectors represent the field's magnitude (position is given in centimeters and electric field strength is given in newtons/coulomb). Restart. a. Determine the unknown charge in coulombs. b. Is the charge due to an excess of electrons or a deficit of electrons? c. Calculate the number of electrons (excess or deficit) that are needed to produce the observed field