The energy of a photon is the frequency multiplied by the Planck constant; E = hf, and the wavelength of a wave is its speed divided by it's frequency; v=flambda => f = \frac{v}{lambda}, so it's energy, E = \frac{hv}{lambda}. This rearranges to lambda = \frac{hv}{E}, where h is the Planck constant, v is the speed of light, and E is the energy of the photon :. lambda = \frac{6.63*10^{-34}*3.0*10^8}{3.083*10^12} = 6.4515*10^-38m
= 6.4515*10^-29nm
I guess that you meant to write 3.083*10^{-12} not 3.083*10^{12}, seeing as gamma rays have a wavelength of ~10^-11m, which is ~10^-18 times larger.
If E = 3.083*10^-12J, using the same method, it would give a wavelength of 6.4515*10^-5nm, which is a reasonable value for electromagnetic waves.
