Question

udent Name: A monochromatic light beam of 105 nm wavelength is incident on a barium target that has a work function of 2.50 eV (a) What is the maximum kinetic energy of the photoelectrons in units of ev? (5 points) The measured kinetic energy of the photoelectrons is lower than the calculated kinetic energy from the previous question. Why? (b) (10 points) tum of the photoelectron (p) based on the answer from question (a) in SI units. the classical relationship between momentum (p), kinetic energy (KE), and mass (m): (c) Calculate the momentum the relation Hint: You can use KE-2 5 points) the difference between the initial photon momentum and the photoelectron momentum calculated in question (c). Why does this difference occur? (10 points)

Answer 1

Wavelenth of incident light -105 nm hc 1240 105 Energy of incident photonE- _- _ eV = 1 1.809 eV From photoelectric eqati on where Wis work function Kis maximum kinetic energy of photo electron (a) K-E-W 11.809-2.50 9309eV (b) Because some energy may converts in to heat (c) momentum of electron P = /2Km = 2 9.309×1.6×10-19 J) (9. 1x10-31 Kg) = 1.6464×10 25 (d)Difference between inital photon momentum and photoelectron momentum is Kg m/s 1.6464x102. 11.809x 1.6x1019 1.6464×10.25-00629810-25 1.5834x10 Kg m/s 3x10 = electron is massive particle