In what region of the electromagnetic spectrum is the frequency of the incident photon

First and foremost, a photon is quantum of light. It is otherwise known as visible light and has a wavelength range of 400 to 700 nm. Moving waves are describable by their frequency (number of waves per second) and wavelengths.

A single photon can be considered unique from other photons only by its energy. In empty space (vacuum), all photons have the same speed or velocity. 

The frequency of the electromagnetic vibration, we know as light, is given in units of Hertz. One hertz is equivalent to one vibration per second; it must be noted that the range of spectrum perceived by the eye extends from 4.3 x 10∧ 14 Hz in the red to about 7.5 x 10∧ 14 Hz in the violet.

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