# Gaussian surface in a charged infinite plance sheet

The following question arises on the use of Gauss law. In the charged finite sheet problem, we consider a Gaussian surface on only one side of the sheet. But, In the case of an infinite sheet, we consider two sides for Gaussian surface. Why? I couldn't catch this idea.

-
How do you use it in finite sheet problem. Plz. Tell. –  ABC Apr 22 '13 at 12:08