If let , then we can say that because the potential energy at this point must be zero. Thus, taking the reference point of zero potential as infinity, . We can use to determine the electric potential due to simple charge distributions by considering the charge distribution to consist of many point charges. Determine the electric potential at point P, a distance a from one end of the rod as shown. Hence the potential at point P due to all the elements is given by show that To check an equation, always try extreme limits and see if the equation simplifies to what you expected.
Q Let r be the distance from the center of the spherical shell to the closed surface.
The net electric field within the thickness of the shell is zero.