For all systems where a beam is traveling from a region with higher index of refraction to a region with a lower index, there is a special angle at which all radiation is reflected on the interface.
If the beam is traveling from the region with higher index of refraction to a region with a lower index of refraction, and if the angle of incidence is greater to the critical angle, then, there is total internal reflection, which means that all radiation of the beam is reflected on the surface of the second region to travel on the first region. Then, you can conclude:
a. The angle of refraction is not a real number because the beam is totaly reflected.
b. after strinking the reflecting surface the beam is totaly reflected to the region of higher index of refraction.
c. This phenomenon is named total internal reflection