Q: Compute the energy of a photon emitted when a CO molecule drops from J = 1 to J = 0. E(J = 1) = 0.00023825 eV E(J = 0) = 0 eV So the energy of the photon is 0.00023825 eV Q: What is the wavelength of this photon? 1240 eV-nm lambda = -------------- = 2.601 x 10^(6) nm 0.00023825 eV = 2.601 mm