RT cores specifically accelerate the key math needed to trace virtual rays of light through a scene. Although, with ray tracing the rays are actually fired from the “eye” into the scene.

How does RT core work?

The RT cores comprises of two specialized units. The first carries out the bounding box tests, while the second performs ray-triangle intersection tests and reports on whether it's a hit or not back to the SM. This frees up the SM to do other graphics or compute work.

What are RT cores and Tensor cores?

The RT cores are much more specialised, but the Tensor cores have at least some breadth of use thanks to the INT4/8 and FP16 capabilities. As a layman I don't know whether there would be any use in offloading tasks or otherwise program the cores for other purposes.