Final answer:
The equipotentials for two point charges q located at (r,0,0) are spheres centered at the origin. Therefore, the correct answer is c. Spheres centered at the origin.
Step-by-step explanation:
The equipotentials for two point charges q located at (r,0,0) are c. Spheres centered at the origin.
Equipotential lines represent places where the electric potential is constant. For two point charges with opposite signs, the equipotentials are spheres centered at the origin. Each point on the surface of the sphere has the same electric potential.
Example 7.19 explains how to calculate equipotential lines for a single point charge.
Equipotential surfaces for point charges are spherical surfaces centered at the location of the charges. In the case where charges are located at (r,0,0), these will not be circles in the xy-plane, lines along the x-axis, or parabolas in the yz-plane; rather, the correct answer is spheres centered at the origin.
This is because the electric potential for a point charge is given by the equation V = kQ/r, indicating that the same potential V occurs at all points that are the same radial distance r from the charge, hence forming a sphere.