Answer: True
Explanation: Frequency by definition is the number of waves that pass a fixed point given a certain amount of time. The shorter the wavelength, the higher the frequency.
Answer:

A typical human eye will respond to wavelengths from 390 to 710 nm (in vacuum or air). In terms of frequency this corresponds to a band in the vicinity of 420–790 THz.
I think it's 10 but i may not be right so, sorry if it's wrong lol