Since you're interested in physics, that often means research, and that requires a PhD. Some time back interesteddad compiled a list of the top 100 schools in the country by percentage of all undergrads (not just physics majors) who later earn a PhD in physics/astronomy; UPenn was not on the list (which is why I stopped at 10/13). Here are the top ten (13 with ties):
PhDs and Doctoral Degrees:
ten years (1994 to 2003) from NSF database
Number of Undergraduates:
ten years (1989 to 1998) from IPEDS database
Formula: Total PhDs divided by Total Grads, multiplied by 1000
Note: Does not include colleges with less than 1000 graduates over the ten year period
1 California Institute of Technology 96
2 Harvey Mudd College 64
3 Massachusetts Institute of Technology 29
4 New Mexico Institute of Mining and Technology 20
5 Reed College 13
6 Carleton College 13
7 Princeton University 13
8 University of Chicago 13
9 Rice University 13
10 Case Western Reserve University 9
11 Harvard University 9
12 Rensselaer Polytechnic Institute 9
13 Swarthmore College 9
Plus, Reed is the only school in the country with a nuclear reactor run by undergrads.
Reed also has a strong religion program:
Reed College Department of Religion