Show that, in a li. h. nonconducting region rather 'where 0 and j, 0, the fields e and b can be found completely from a vector potential, that is, ф-const. (zero is usually chosen). what two first. equations determine a? etiza- time, m oten- 22-7 consider a region where p,-0, j, -0, =0, while p is a given function of posi- the tion and time. show that (22-4) and (22-5) nd can be satisfied and the electromagnetic field ob- such that a l from a single vector