$[3$B$]$ Two parallel infinite conducting plates with the areas $0\mathrm{.}5$ m$2$ have the same magnitude of surface charge density s $=1$ microC$/$m$2.$ One plate has the electric potential $+60$ V and another has the electric potential $130$ V$.$ What are the $($b$)$ direction $(+$ or $-)$ and magnitude of electric field $($in kV$/$m$)$ between the plates?$[3$B$]$ Two parallel infinite conducting plates with the areas $0\mathrm{.}5$ m$2$ have the same magnitude of surface charge density s $=1$ microC$/$m$2.$ One plate has the electric potential $+60$ V and another has the electric potential $130$ V$.$ What are the $($b$)$ direction $(+$ or $-)$ and magnitude of electric field $($in kV$/$m$)$ between the plates?