question about electives

quilibet

hi,
i am not sure here is tehe correct forum but i have a little problem
i am a 3rd year undergratuate student in math and took some physics lectures like quantum, classical physics.Now i begin to think becoming a
physicist(if i can)In a few days i have to decide about which elective courses to take/ group theory ,an analysis course and set theory + 2 must course. i am sure about first two but not so for set theory
Can it be usefull in physics or just a waste of time?