The Wavelength of Coherent Ruby Laser Light Is 694 Nm

Multiple Choice

The wavelength of coherent ruby laser light is 694 nm.What energy difference exists between the upper excited state involved and the lower unexcited ground state? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A) 0.56 eV
B) 1.79 eV
C) 1.67 eV
D) 2.87 eV
E) ​0.35 eV