1. The problem statement, all variables and given/known data 2. Relevant equations V = q/(4*pi*E_0*r), when 0 is taken at infinity dV = -E*ds 3. The attempt at a solution a. The total charge of the rod is given by Q = lambda*L So the potential at P is given by V = (lambda*L)/(4*pi*E_0*y) b. We can calculate the electric field by differentiating part a with respect to y to get: E = -(lambda*L)/(4*pi*E_0*y^2)*y-hat c. Because point P is along the axis of the rod, there is no x-component to the electric field.