Question

Calculate the maximum kinetic energy (eV) of a photo electron for a radiation of wave length 4000 A° incident on a surface of metal having work function 2 eV ?

Answer 1

Here is your answer, in general, the Wavelength of light will be (λ) = 5000 Å=5000×10−10=5×10−7m as well as the Work function (ℎv) =1.9eV =1.9×1.6×10−19J=3.04×10−19 J even the Energy of photons, E=ℎv=ℎc/λ=6.626×10−34×3×1085×10−7=3.97×10−19 J as well as the Kinetic energy of photoelectrons will be =ℎv−ℎv=3.97×10−19−3.04×10−19 =9.3×10−20J.

Overall your answer will be 3×10−20J.