What is the wavelength, k, corresponding to a frequency, w, of 7x10^19 Hz of electromagnetic wave in free space? The speed of light is 2.99792x10^8 m/s. Answer in units of m. I set w/k=c Plugging in (2*pi*7X10^19) for w, and 2.99792x10^8 for c, I got 1.467X10^12. The answer is wrong. Where did I go wrong?