In case of time varying fields we shall see that , which is known as Lorentz condition, V being the electric potential. Here we are dealing with static magnetic field, so .

By comparison, we can write the solution for Ax as

  ...................................(4.30)

Computing similar solutions for other two components of the vector potential, the vector potential can be written as

.......................................(4.31)

This equation enables us to find the vector potential at a given point because of a volume current density . Similarly for line or surface current density we can write