Lasers: in a Ruby Laser, an Electron Jumps from a Higher

Lasers: In a ruby laser, an electron jumps from a higher energy level to a lower one. If the energy difference between the two levels is 1.8 eV, what is the wavelength of the emitted photon? (c = 3.00 × 10⁸ m/s, h = 6.626 × 10^-34 J ∙ s, 1 eV = 1.60 × 10^-19 J)

A) 350 nm
B) 470 nm
C) 650 nm
D) 690 nm
E) 960 nm