Question

Question #657d6

Answer 1

The magnetic field is given by the curl of the vector potential, `A`.

`B=\nabla\times A`

Explanation:

The vector potential , `A` , is used because it often provides an easier way to find `B`.

It is analogous to how the electric field, `E`, can be derived from the scalar potential `V`. `\quad \quad\quadE=\nabla V`

`A` can be calculated by:

`A=\mu_0/{4\pi}\intJ_{(r)}/{r-r_0}dV`

where `J` is the current density at the point `r`. This expression comes from the Helmholtz Theorem.