I've stumbled upon this question on a CG exam:
Which of the following techniques/optimizations doesn't apply to ray tracing?
A: Back-face culling
B: "Shadow-feeler" rays
C: Recursive tracing of rays
D: Calculation of refraction rays
E: None of the above
B, C and D are obviously false, but what about A? Here, is says that "with ray tracing, this feature is not as useful. Generally with ray tracing, we want geometry in the scene to cast shadows for example, regardless of the orientation of the object's surface with respect to the ray direction however the backface culling option might still be desired for primary rays".
I feel that the question is a bit ambiguous, since back-face culling can be applied to ray tracing but it's not (correct me if I'm wrong) a "native" feature as the other techniques.