The formuka to calculate energy of photon is
E=hc/ Lambda
where h is planks constant
c is velocity of light in vaccume
lamda is the wavelength.
Now
h= 6.626×10^-34 J s
c= 3×10^8 m/s
lamda=350 nanometers= 350×10^-9 m
hence
E=(6.626×10^-34×3×10^8)/(350×+0^-9)
=(19.878×10^-26)/(350×10^-9)
=0.567×10^-17
=5.67×10^-16 J
