Application

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.

Activities

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^{-9}C*( hint: calculate the charge 3
times, find the average rate up to two decimal digits) *