Graduate students typically spend the first year and most of the second taking courses. In addition to required courses in electromagnetism, quantum mechanics, and statistical mechanics, there are elective courses in areas ranging from quantum field theory to solid-state physics. Students who have previously taken graduate-level courses can be excused from required courses by passing exemption examinations on first entering the program. First-year graduate students take a written qualifying exam in January. The three half-day exams cover classical and modern physics. Most students pass this examination on the first attempt; a smaller number retake and pass the examination the following year.