Final answer:
The charge of the particle can be found using the electric force and electric field strength.
Step-by-step explanation:
The question asks for the charge of a particle placed on the x-axis in a region where the electric potential changes only in the x direction. To determine the charge, we are given the electric force, which can be calculated using the charge and electric field strength. The electric force is found to be
F = (3.20×10-19 C)(3.00×105 N/C) = 9.60×10-14 N.