Short wavelengths.
To correct your selling, it is 'opposite', NOT 'oppersite'. Red is a colour at the long wavelength end of the spectrum . So its opposite is Blue a colour that is at the short wavelength ends of the spectrum.
Short wavelength
There is no longest wavelength for photons. It can be arbitrarily long.
It depends on what you consider high frequency and long wavelength. However, as frequency increases, wavelength decreases and vice versa. In fact, frequency is inversely proportional to wavelength.
Long
I looked it up in my physics text book and it says that the wavelength is too long to be seen by the human eye.
The opposite of long is.... short.
Macroscopic things which could be seen by naked eye and under visible wavelength of light are considered opposite to Elementary particles !
23
The wavelength of infrared light is too long for humans to see.
In length, the opposite of long is short. In time, the opposite of long may be short or brief.
How long is your co-ax???