Question

Light of wavelength 4000 Å is incident on a sodium surface for which the threshold wavelength of photoelectrons is 5420 Å. The work function of sodium is
A. 0.57 eV
B. 1.14 eV
C. 2.29 eV
D. 4.58 eV

Answer 1

Correct Answer - C
As `phi_(0)=(hc)/(elamda_(0))` (in eV)
`=(6.62xx10^(-34)xx3xx10^(8))/(5420xx10^(-10)xx1.6xx10^(-19))=2.29eV`