Problem $10\mathrm{.}3($a$)$ Find the fields, and the charge and current distributions, corresponding to V$($r$,$ t$)=0,$ A$($r$,$ t$)=14$$0$ qt r $2$ r$.($b$)$ Use the gauge function $=(1/4$$0)($qt$/$r$)$ to transform the potentials, and comment on the result.