On the left picture there is an unknown charge (Q) immobile at the center of the picture and a test charge (black color, q). On the graph to the right you see the force as a function of the distance between the two charges.
You can move the q charge
using the mouse. Drag it to positions A, B and C, and measure the force using the graph.
Question: In which of the 3 positions has the force the lowest rate?
Exercise: Can you calculate the Q charge? Given that q=10-9C(hint: calculate the charge 3 times, find the average rate up to two decimal digits)