What is the number of photons of light with a wavelength of 4000 pm that provide 1J of energy?





Q.8:- What is the number of photons of light with a wavelength of 4000 pm that provide 1J of energy?

 

Answer:-
λ = 4000 pm = 4000×10-12 m = 4×10-9 m
E = Nhν = Nhc/λ
∴ N = E×λ/h×c = (1J×4×10-9 m)/(6.626×10-34 Js×3.0×10ms-1) = 2.012×1016 photons.