Electrons are emitted from a surface when light of wavelength 500 nm is shone on the surface but electrons are not emitted for longer wavelengths of light. The work function of the surface is
A)5.0 eV.
B)0.60 eV.
C)2.5 eV.
D)4.0 eV.
E)0.40 eV.

Question

Quizplus · Accepted Answer

The work function is the minimum energy needed to emit electrons from a surface. Using the equation $E = \frac{hc}{\lambda}$, where $h$ is Planck's constant, $c$ is the speed of light, and $\lambda$ is the wavelength, we find the energy for 500 nm light is approximately 2.5 eV. This is the work function since longer wavelengths (lower energy) do not emit electrons.

Electrons Are Emitted from a Surface When Light of Wavelength