The work function for mercury is equivalent to 435kJ/mol photons. What is the kinetic energy, in joules, of the ejected electrons when light of 188 nm strikes a mercury surface?

I know the equation for work function (w) is E+w=hf but I don't know where to go from there...
w=435 kJ

1 Answer
P dilip_k
Nov 12, 2016

Einstein photo electric equation

Ek+w=hf

Where

Ek→KE of ejected electron

w→photo electric work function=435 kJ/mol

=435×1000Jmol6.023×1023mol−1=7.22×10−19J

h→Planck's constant=6.62×10−34Js

f→frequency of incident light=cλ
=3×108ms188×10−9m=3188×1017Hz

where velocity of radiation c=3×108ms
and wave length of radiation λ=188nm=188×10−9m

Now

Ek+w=hf

⇒Ek=6.62×10−34×3188×1017−7.22×10−19J
≈10.56×10−19−7.22×10−19J=3.34×10−19J

Related questions
See all questions in Calculations with wavelength and frequency
Impact of this question
10831 views around the world
You can reuse this answer
Creative Commons License