The photon energy corresponding to the red border of the photoelectric effect for potassium is 7.2 * 10 ^ (- 19) J.

| August 2, 2021 | education

The photon energy corresponding to the red border of the photoelectric effect for potassium is 7.2 * 10 ^ (- 19) J. Determine the maximum kinetic energy of photoelectrons if light falls on the metal. whose photon energy is 10 ^ (- 18) J.

Av = 7.2 * 10 ^ -19 m.

Eph = 10 ^ -18 J.

Ekmax -?

The energy of the incident photons Eph goes to knock out electrons from the surface of the metal Av and impart kinetic energy Ekmax to them.

Eph = Av + ​​Ekmax.

The energy that is sufficient to snatch an electron from the surface of the metal is called the red border of this metal.

The maximum kinetic energy of electrons Ekmax will be the difference between the energy of the incident photons Eph and the energy of the red boundary of the given metal Av: Ekmax = Ef – Av.

Ekmax = 10 * 10 ^ -19 J – 7.2 * 10 ^ -19 J = 2.8 * 10 ^ -19 J.

Answer: when leaving the potassium surface, electrons can have a maximum kinetic energy Ekmax = 2.8 * 10 ^ -19 J.



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