  We discuss the development and evaluation of five research-based tutorials on
Coulomb's law, superposition, symmetry and Gauss's Law to help students in the
calculus-based introductory physics courses learn these concepts. We discuss
the performance of students on the pre-/post-tests given before and after the
tutorials in three calculus-based introductory physics courses. We also discuss
the performance of students who used the tutorials and those who did not use it
on a multiple-choice test which employs concepts covered in the tutorials.
