These four questions will help your students think about potential

I have been going through a lot of the clicker-type conceptual physics questions that I have collected over the years from other physics teachers who have been gracious enough to share them, when I came across a sequence of four questions related to the potential and potential energy of a three charge system.

I really like the set of questions, but I’m looking for some feedback from other teachers on how to best use them.

Here’s the system:

Three charges form a triangle at points 1, 2 and 3. The electrical potential at q₃ has some value V₃. (This setup of the system is the same for all four questions below.)

Here are the questions:

1. If the charge of q₃ is doubled, the value of the electrical potential at the point 3 will:
   A.) increase by a factor of two
   B.) increase by a factor of four
   C.) decrease by a factor of two
   D.) decrease by a factor of four
   E.) remain the same
2. If the charges q₁, q₂, and q₃ is doubled, the value of the electrical potential at point 3 will:
   A.) increase by a factor of two
   B.) increase by a factor of four
   C.) increase by a factor of eight
   D.) decrease by a factor of four
   E.) remain the same
3. If the charge of q₃ is doubled, the value of the electrical…