An electron undergoes a transition from an initial (ni) to a final (nf ) energy state. The energies of the ni and nf energy states are −5.450×10−19J and −8.720×10−20 J, respectively.
Calculate the wavelength (λ) of the light in nanometers (nm) corresponding to the energy change (ΔE) value of this transition. You can use the following values for your calculations:
Planck′s constant (h)speed of light (c)1 m===6.626×10−34 J⋅s2.998×108 m/s109 nm

Question

An electron undergoes a transition from an initial (ni) to a final (nf ) energy state. The energies of the ni and nf  energy states are −5.450×10−19J and −8.720×10−20 J, respectively.
Calculate the wavelength (λ) of the light in nanometers (nm) corresponding to the energy change (ΔE) value of this transition. You can use the following values for your calculations:
Planck′s constant (h)speed of light (c)1 m===6.626×10−34 J⋅s2.998×108 m/s109 nm