On the Idea of Black-Holes - Their Characterization Along with an Attempt to Classify them Properly

The term 'Black-Hole' is very common to almost all people in the world at present. A black-hole (B-hole) is one from which even light cannot come out from its surface. How many types of B-holes are possible in the universe and which of them are to be recognized as real B-holes and why? What will be the composition, density and volume of a B-hole? Is it possible for a B-hole to attain singularity? All these things are discussed below.