Is it possible to be accepted into a physics intership with a low GPA?
Possible? Sure. Likely? That depends on how low is low. Also "physics internship" is not well defined - for professionals, this usually means grad school, which is difficult with a low GPA. Assuming you mean "college internship open to physics majors", my original answer stands.
What GPA are we talking about (I mean in numbers)? When I was in undergrad I had a professor who said that if his undergrad researchers started slipping on their homework assignments, he'd pull them out of the lab until they shaped up. Usually GPA is considered for research and summer REU programs. As Vanadium 50 asked: how low is low? If you have a 2.8-3.0, you'll probably find a professor to take you on. I have a senior undergrad friend in my department who has a GPA in that regime, and who did a summer at FermiLab. But if you've got something dismal, like in the 2.0 range, your chances are pretty slim.
Separate names with a comma.