What's The Wavelength Of Light In (nm) That Has The Frequency Of 10^5 Hz?

Visible light has wavelengths from 380 nm to 750 nm. 

Since the speed of light is roughly 300,000,000 meters per second (or 186,000 miles per second), the frequency range is from 400 TeraHertz (400 x 10¹²) to 790 TeraHertz (790 x 10¹²).

10⁵ is a frequency typical for a high pitched audio wave.  Only a person with synesthesia would perceive colors from that.

The wavelength is computed from
(speed of light) = (wavelength)*(frequency)

Since you want it in nanometers
3*10¹⁷ nm/sec = wavelength*(10⁵/sec)
(3*10¹⁷*10^-5) nm = wavelength    (divide both sides by 10⁵/sec)

3*10¹² nm = wavelength

As noted by Nic7320, this 3000 meter wavelength is way outside the visible range. It is in the low frequency band of the electromagnetic spectrum.