The last page of each quiz has an answer key. Note that it may have errors, and it is not very detailed.

Quiz 1 - Electric field
Quiz 2 - Polarization
Quiz 3 - Electric field of distributed charge
Quiz 4 - Electric potential
Quiz 5 - Magnetic field
Quiz 6 - Circuits
Quiz 7 - Magnetic force
Quiz 8 - Electric and magnetic flux
Quiz 9 - Electromagnetic Radiation
Midterm Exam - covers topics on quizzes 1-5