Question

To determine the work function of a material of a photodiode, you measuered the maximum Knetic energy of .5 eV correwsponding to a certain wavelength. Later on, you cut down the wavelength by 50% and found the maximum kinetic energy of the photoelectrons to be 3.8eV. From this information determine
a) work function of the material, and
b) the original wavelength.

Answer 1

E1(max) = 0.5 eV = hc/L1 - phi
E2(max) = 3.8 eV = 2hc/L1 - phi
where
L1 = first wavelength
L1/2 = second wavelength
phi = work function
3.3 eV = hc/L1
b) Solve for L1 first
a) Then solve for phi