(a) A very large metal plate of surface area \(A\) carries a positive charge \(q\). What is the surface charge density of the plate? What is the magnitude of the field created by the plate? 

(b) A very large, thin nonconducting sheet of surface area \(A\) carries a fixed, uniformly distributed positive charge \(q\). What is the surface charge density of the sheet? What is the magnitude of the field created by the sheet?