Energy:

$\overline{){\mathbf{E}}{\mathbf{=}}\frac{\mathbf{h}\mathbf{c}}{\mathbf{\lambda}}}$

λ = hc/E

__At 2.0 eV - 1.0 eV = 1.0 eV__

The allowed energies of a quantum system are 1.0 eV, 2.0 eV, 4.0 eV, and 7.0 eV. What wavelengths appear in the system's emission spectrum (in nanometers)?