1See it actually depends on the iit you opt for.
In iitm ive seen these people doing a lot of courses in common with the electrical engineering students.
In iitb i believe it is quite different. They teach you subjects like nano sciences.
donno about iitd
Where ever you take ep, make sure you have interest for physics, and enthusiasm for research in it. Because Ive heard a lot of people going for it with no interest and just because their rank permitted them to take it, and cribbing later on.
cheers!