Two students A and B were taught that electric field near a uniformly charged large surface is normal to the surface and is equal to `(sigma)/(2 in_(0))`. They were also told that field near the surface of a conductor is `(sigma)/(in_(0))` normal to the conductor where s is charge density on the conductor surface. Now both of them were asked to write field between the plates of an ideal parallel plate capacitor having charge density `sigma` and `-sigma` on its plates. Student A said that field can be seen as superposition of field due to two large charged surfaces. He wrote the answer as
`E=(sigma)/(2in_(0))+(sigma)/(2in_(0))=(sigma)/(in_(0))`
Student B thought that a capacitor has conducting plates and therefore field due to each plate
Must be `(sigma)/(in_(0))` . He wrote his answer as `E=(sigma)/(in_(0))+(sigma)/(in_(0))=(2sigma)/(in_(0))`
Who is wrong and where is the flaw in thinking ?

Answer

B is wrong