I need help on this one

Question

Assume that most of the electromagnetic energy from the sun is the visible region near 500 nm. Calculate the maximum value of the work function for a metal to be used in photovoltaic cells to convert solar energy into electicity.

Answer 1

Assuming the work function W cannot exceed the energy of a single photon of wavelength λ,

 

W_max = h(c/λ)

 

h = Planck's constant = 6.63 x 10^-34 J s

 

c = speed of light = 3 x 10^8 m/s

 

λ = 500 nm = 500 x 10^-9 m

 

W_max = (6.63 x 10^-34 J s) (3 x 10^8 m/s) / (500 x 10^-9 m) = 3.978 x 10^-19 J