The energy of a photon is given by
[tex]E=hf[/tex]
where
[tex]h=6.6 \cdot 10^{-34} Js[/tex] is the Planck constant
f is the frequency of the photon
In our problem, the frequency of the light is
[tex]f=5.49 \cdot 10^{14}Hz[/tex]
therefore we can use the previous equation to calculate the energy of each photon of the green light emitted by the lamp:
[tex]E=hf=(6.6 \cdot 10^{-34}Js)(5.49 \cdot 10^{14} Hz)=3.62 \cdot 10^{-19} J[/tex]
