The surface of lithium is irradiated with light at a frequency of 10.15 Hz. Determine the maximum kinetic energy

| March 1, 2021 | education

The surface of lithium is irradiated with light at a frequency of 10.15 Hz. Determine the maximum kinetic energy of photoelectrons if the work function of electrons from lithium is 2.4 eV

Let’s find the radiation energy using the Planck formula:

E = h * η, where h is Planck’s constant (6.63 * 10 ^ (- 34) J * s, η is the frequency.

Substituting the given frequency value, we get:

E = 6.63 * 10 ^ (- 34) * 10 ^ 15 = 6.63 * 10 ^ (- 19).

Let us express the resulting value in electron volts, for this we divide it by the electron charge:

E = 6.63 * 10 ^ (- 19) / 1.6 * 10 ^ (- 19) = 4.14 eV.

The energy of photoelectrons will be equal to the difference between the radiation energy and the work function:

4.14 – 2.4 = 1.74 eV.

Answer: the required energy is 1.74 eV.



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