The red border of the photoelectric effect for metal is 3 * 10 ^ 14 Hz. Determine the work function

The red border of the photoelectric effect for metal is 3 * 10 ^ 14 Hz. Determine the work function for this metal and the kinetic energy of photoelectrons if light falls on the metal with a frequency of 3 * 10 ^ 14 Hz

1. Let us write down the Einstein equation for the photoelectric effect:

h * ν = A + Tmax, where A is the work function of an electron from the metal, Tmax is the maximum kinetic energy of photoelectrons, h * ν is the energy of a photon.
2. At the cutoff frequency νcr, Tmax = 0
So the work function of an electron is determined by the expression:
A = h * νcr
h = 6.63 * 10 ^ -34 J * c- Planck’s constant.
3. Let us determine the work function of the electron:
A = h * νcr = 6.63 * 10 ^ -34 * 3 * 10 ^ 14 = 1.99 * 10 ^ -19 J.

Answer: the kinetic energy of photoelectrons is zero, and the work function of the electron is 1.99 * 10 ^ -19 J or 1.24 eV.