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. Barium has a work function of 2.48eV. What is the maximum kinetic energy if the metal is illuminated by UV light of wavelength 365nm?​

Sagot :

The maximum kinetic energy is 0.91 eV

What is Work Function of a Metal ?

A Work Function of a Metal is the minimum energy required to liberate an electron from a metal surface. From the formula;

hF = hf + E

  • hF = energy for liberation or illumination
  • hf = work function = 2.8 eV
  • E = kinetic energy

Given that a Barium has a work function of 2.48eV. What is the maximum kinetic energy ?

Convert eV to Joule by multiplying by 1.6 x [tex]10^{-19}[/tex]

hf = 2.48 x 1.6 x [tex]10^{-19}[/tex]

hf = 3.968 x [tex]10^{-19}[/tex] J

If the metal is illuminated by UV light of wavelength 365nm,

E = hF = hc/λ

Where

  • C = speed of light = 3 x [tex]10^{8}[/tex] m/s
  • h = Planck constant = 6.6 x [tex]10^{-34}[/tex] Js
  • λ = wavelength = 365 x [tex]10^{-9}[/tex] m

Substitute all the parameters

hF = (6.6 x [tex]10^{-34}[/tex] x  3 x [tex]10^{8}[/tex]) / 365 x [tex]10^{-9}[/tex]

hF = 1.98 x [tex]10^{-25}[/tex] /  365 x [tex]10^{-9}[/tex]

hF = 5.42 x [tex]10^{-19}[/tex] Joule

The maximum kinetic energy will be

hF = hf + E

Make E the subject of formula

E = hF - hf

E = 5.42 x [tex]10^{-19}[/tex] - 3.968 x [tex]10^{-19}[/tex]

E = 1.452 x [tex]10^{-19}[/tex] J

Convert Joule back to eV by dividing by 1.6 x [tex]10^{-19}[/tex]

E = 1.452 x [tex]10^{-19}[/tex] / 1.6 x [tex]10^{-19}[/tex]

E = 0.9075 eV

Therefore, the maximum kinetic energy is 0.91 eV approximately

Learn more about Work Function here: https://brainly.com/question/14144692

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