One fixed charge and one “test” charge are shown in each animation. The
fixed charge is labeled by an “f” and the test charge is labeled by a
“t”. You can click-drag on the "test" charge to change its
position. There are three animations depicted.
which animation is the “test” charge a true “test” charge?
Reference: See Giancoli-PA: 16-7, Giancoli-SE: 21-6.
Animation 3. As the “test” charge is moved in each
animation, the field changes or remains the same. The animation where the test
charge leaves the original field unaffected is the correct animation. This is of
course the definition of the test charge to begin with. It is important for
students to grasp the fact that in the course of measuring the field of the
fixed charge, one may disturb the field if one uses a real charge. Note that this
is also Problem 9.1.2 here used without major modification as an in-class
Script Author: Mario Belloni