The number of physics degrees earned by African Americans is very small. Even a few added each year is a significant contribution.
In the year 2003, 4% of the bachelor's degrees in physics (152) awarded nationally were awarded to African Americans. For Master's degrees the numbers are 4% (15) and for Physics Ph.D. degrees 2% (the latter represents only about 12 Ph.D. degrees awarded) (source: AIP). Many of these undergraduate degrees come from HBCUs, and Hampton University contributes a significant fraction of Ph.D. graduates.
According to data collected by the AIP, the nine institutions producing three or more AA physics bachelor's graduates per year (2001-2003) were all HBCUs. Hampton University ranked third in this list.
According to the HU School of Science:
A listing of HBCUs can be found at the web page for the President's Board of Advisors on Historically Black Colleges and Universities.