Assertion (A) : The images formed by total internal reflections are much brighter than those formed by mirrors or lenses.
Reason (R) : There is no loss of intensity in total internal reflection.

In total internal reflection 100% of incident like reflected back into the same medium and there is no loss of intensity. While in reflection from mirrors and refraction lenses, there is always some loss of intensity. Therefore images formed by total internal reflection or much brighter than those formed by mirrors or lenses.