Two plates extend the same distance into the page. Their heights, projected onto the vertical axis, are the same. What is the area of plate 2, compared with the area of plate 1? A] same B] C] D] 

If the dot product of E and the area of plate 1 is EA 1, what is the dot product of E and the area of plate 2? A] same B] C] D]  

What would happen to the flux if we were to double the field? A] same B] double C] half D] quadruple  

The flux is proportional to the field, and to the perpendicular area. We know the density of field lines (#lines per perpendicular area) is proportional to the field. So the flux is proportional to the number of field lines penetrating a surface area. Note: the sign depends on how we “orient” the surface!  

Does the total flux through a spherical surface at radius R change if we move the charge off-center? A] yes B] no

Does the total flux through a closed surface surrounding a point charge change is we distort the surface (while keeping it closed)? A] yes B] no

Gauss’ Law is useful for finding E fields when there is symmetry. Sphere of charge Line of charge Sheet of charge Gauss’ law also shows that excess charge on a conductor is all at the surface!

A small sphere and a short rod have the same charge Q. Gauss’ Law allows us to conclude that the electric field a distance r away from each (if looked at separately) would be the same. A] True B] False FALSE! There is not enough symmetry to use Gauss with the finite rod!!!!!!