Question

If an electromagnetic wave from crest to crest measured 30 nanometers what kind of wave would it be

Answer 1

Well, I recognize them by frequency, so let's see . . .

Frequency = (speed) / (wavelength)

Speed = around 3 x 10⁸ m/s in vacuum

Frequency = (3 x 10⁸ m/s) / (30 x 10⁻⁹ m) = 1 x 10¹⁶ Hz.

That's a frequency I don't recognize,
so I gotta go lookit up.

30 nanometers is a hard hard X-ray.
At 10¹⁹ Hz . . . 1,000 times higher freq/shorter wavelength . . .
it would be considered a gamma ray.  But this one is just a
hard, hard X-ray.