A solid metal sphere with radius 0.450 $\mathrm{m}$ carries a net charge of 0.250 $\mathrm{nC}$ . Find the magnitude of the electric field (a) at a point 0.100 $\mathrm{m}$ outside the surface of the sphere and (b) at a point inside the sphere, 0.100 $\mathrm{m}$ below the surface.