ECE106 Lecture 20: ECE 106,University of Waterloo,(p20)

• School: University of Waterloo
• Department: Electrical and Computer Engineering
• Course: ECE106
• Professor: All

Document Summary

So far we have done an open surface. Now let us fully close this surface (i. e. like a cube or a sphere). you cannot get in or out of the surface without penetrating through it. In this case, the normal to the surface is always from the inside towards the outside. The circle reminds us that the integral is a closed surface. It would mean that what ever flows in, flows out. If > 0, more flows out than flowing into the closed surface. Lets surround it by a sphere of radius r. E and d s are in the same direction! If instead of a sphere we have an arbitrarily shaped surface, even then, = q . s.