The Planck–Einstein relation [tex]E=hv[/tex] gives that E, the photon energy, is equal to h, Planck's constant, times ν, the frequency.
We can solve the equation in terms of frequency to get
[tex]v= \dfrac{E}{h} [/tex]
We substitute our given energy, [tex]8.10 \times 10^{-19} J[/tex], and Planck's constant, [tex]6.626 \times 10^{-34} Js[/tex].
[tex]v= \dfrac{8.10 \times 10^{-19} J}{6.626 \times 10^{-34} Js}=1.22 \times 10^{15} s^{-1}=1.22 \times 10^{15} Hz[/tex]
