“Write down Gauss' Law.”
This SWBQ can be done as an introduction to the Gauss' Law lecture. It is an opportunity for the instructor to find out what the students already know about Gauss' so as to focus the succeeding lecture/discussion appropriately.
Since most students remember something about this law, one can construct the answer on the front board from the bits and pieces that they remember, emphasizing why each of the pieces is important and talking about the geometry of each piece.