A photon of radiation of wavelength 305 nm ejects an electron from a metal with kinetic energy 1.77 eV. What is the maximum wavelength capable of ejecting an electron from the metal?
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1 eV = 1.60E-19 J, so 1.77 eV = 2.84E-19 J
E = hc/w = 6.626E-34 * 3E8 / 305E-9 = 6.52E-19 J
KE = E(photon) - WorkFunction = 6.52E-19 - 2.84E-19 = 3.68E-19 J
E = hc/w
w = hc/E = 6.626E-34 * 3E8 / 3.68E-19 = 5.41E-7 m = 541 nm
E = hc/w = 6.626E-34 * 3E8 / 305E-9 = 6.52E-19 J
KE = E(photon) - WorkFunction = 6.52E-19 - 2.84E-19 = 3.68E-19 J
E = hc/w
w = hc/E = 6.626E-34 * 3E8 / 3.68E-19 = 5.41E-7 m = 541 nm