Answer :
Answer:
ultraviolet light (UV) has more energy than blue light, so electrons must have higher kinetic energy
Explanation:
This is a photoelectric effect exercise, which was explained by Einstein assuming that light is composed of photons and that they interact with electrons as particles.
h f = K + Ф
where fi is the work function of the material
K = hf -Ф
the work function for a given material is constant, therefore let's find the energy of each photon
E = h f
c = λ f
f = c /λ
we substitute
E = h c /λ
Blue light λ = 450 nm = 450 10⁻⁹ m
E = 6.63 10⁻³⁴ 3 10⁸/450 10⁻⁹
E = 4.42 10⁻¹⁹ J
UV light λ = 400 nm = 400 10⁻⁹ m
E = 6.63 10⁻³⁴ 3 10⁸/400 10⁻⁹
E = 4.97 10⁻¹⁹ J
therefore ultraviolet light has more energy than blue light, so electrons must have higher kinetic energy