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The work function for sodium metal is 1.82 eV calculate the threshold frequency wavelength for sodium?
Wiki User
∙ 15y ago
If this question is related to the photoelectric effect the answer should be as follows
(but I have learned the work function for sodium is 2.35 eV)
Photoelectric effect: Photon energy h f = W + KE
h := Planck constant
f:= freqency of emitted light
W:= Work function in Joule 1.82 eV * 1.6*10-19 J/eV = 2.91 * 10-19J
KE: kinetic energy of electrons that have been released from metal
When f0 is threshold frequency: KE = 0
(photon energy h*f0 is just enough to free electrons but not to give them kinetic energy)
h*f0 = W
f0 = W/h = 2.91 * 10-19J / 6.63*10-34 Js = 4.39 * 1014 Hz
wavelength = c / f0 = 3.0 * 108 m/s / 4.39 * 1014 Hz = 6.84 * 10-7 m = 684 nm
Wiki User
∙ 15y ago
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