I can give those answers for the computational physics classes I've taught and the physics departments I've seen.
At my previous university, located in the Southwest in a town that is ~40% Hispanic, the physics department student body was perhaps half whites. There were no African-Americans or immigrants from Africa, and some fraction (10%?) of Hispanics*. There were quite a few East Asian immigrants, some Indian immigrants, and some Indian-Americans. There were more immigrants among graduate students than among undergraduates; the only Africans were a few Afrikaaners.
Thinking back to the "best and brightest" students that came through my computational physics course, they were roughly evenly split between men and women; most were white, with two good Hispanic students. Anecdotally, astronomy has many more women than physics, and the course was also taken by astronomers.
At my current university, located in an urban area that is 50% black, there is one black student in the physics program proper: an Ethiopian immigrant. (She is excellent.) There are a small number of black students in service courses; anecdotally, they tend to do worse than their peers, with one notable exception who is strong. There are no New World Hispanics that I can think of; there are two Spaniards. The graduate program has a great many Chinese, some Indians, and some Ukrainians (from these countries), along with white Americans.
So, basically: the people in physics courses (at least) include very few blacks, some Hispanics in Hispanic areas, and whites and Asians, with more Asian immigrants in graduate programs.