Answer:
That's a lot like asking: "How many distances are there between here and Denver ?"
We like to split up the electromagnetic spectrum into sections, and give the sections
different names, like heat, light, radio, x-rays, etc. But those divisions aren't real, and
all electromagnetic radiation is the same physical phenomenon. Any time you name two
different wavelengths, then no matter how close together they are, I can always
name another one that's in between them. There are no edges or boundaries to
the categories. You can go ahead and invent new categories with new names if you
want to, and it doesn't matter how many.