Consider the following energy level diagram for hydrogen:
n = 7
E7 = -4.445 x 10^-20 J
n = 6
E6 = -6.050 x 10^-20 J
n = 5
E5 = -8.712 x 10^-20 J
n = 4
E4 = -1.361 x 10^-19 J
n = 3
E3 = -2.420 x 10^-19 J
What is the wavelength (in nm) of a photon emitted during the transition of an electron from n = 7 to n = 3?