The Wavelength of a Ruby Laser Is $694.3 \mathrm {~nm}$ What Is the Energy Difference Between the Two Energy

Multiple Choice

The wavelength of a ruby laser is $694.3 \mathrm {~nm}$ . What is the energy difference between the two energy states for the transition that produces this light? $\left( c = 3.00 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } , 1 \mathrm { eV } = 1.60 \times 10 ^ { - 19 } \mathrm {~J} , h = 6.626 \right.$ $\times 10 ^ { - 34 } \mathrm {~J} \cdot \mathrm { s }$ )

A) $1.65 \mathrm { eV }$
B) $1.54 \mathrm { eV }$
C) $1.79 \mathrm { eV }$
D) $1.81 \mathrm { eV }$