The work function for a certain metal is 3.00 eV. Calculate the speed of the electrons in m/s ejected by light of wavelength 209 nm. If it is not ejected, report a speed of 0.0.

Answer 1

Energy of incident light = Planck's constant*Frequency of incident light = hν = (hc/λ).

If (hc/λ) > Work Function,
The incident light has enough energy to eject an electron, and the kinetic energy is equal to the difference between (hc/λ) and the Work Function. The speed can be calculated from the kinetic energy (1/2*mv^2)

If (hc/λ) < Work Function,
There is not enough energy to eject the electron and the speed would be 0.0, as ejection would not occur.