If the light of wavelength 412·5 nm is incident on each of the metals given below, which ones will show photoelectric emission and why?
Metal | Work Function (eV) |
Na | 1.92 |
K | 2.15 |
Ca | 3.20 |
Mo | 4.17 |
Given,
The wavelength of the incident light
The energy of the photon
.
We know
Therefore
So the energy of the photon is,
The photoelectric emission takes place only when the energy of the incident photon is more than the work function of the metal.
So, From the give metal only Ca and Mo show the photoelectric emission.