Quick question about PhotoElectric Effect

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SUMMARY

The discussion centers on the behavior of photons in a light beam when their energy is insufficient to release electrons from a metal surface, specifically in the context of the Photoelectric Effect. It is established that photons below the threshold frequency do not release electrons, and thus the overall work function of the material does not decrease. When photons interact with electrons without providing enough energy to expel them, the electrons gain kinetic energy, increasing their random motion and causing the metal to heat up. This heat is eventually transferred to the surroundings, contributing to an increase in the Universe's thermal energy.

PREREQUISITES
  • Understanding of the Photoelectric Effect
  • Familiarity with the equation KE = h*f - Workfunction
  • Knowledge of photon-electron interactions
  • Basic principles of thermodynamics related to heat transfer
NEXT STEPS
  • Study the implications of the Photoelectric Effect in quantum mechanics
  • Explore the concept of threshold frequency in detail
  • Learn about the kinetic energy of electrons in metals
  • Investigate how thermal energy is transferred in solids
USEFUL FOR

Students of physics, educators teaching quantum mechanics, and researchers interested in the thermal effects of light on materials will benefit from this discussion.

kougou
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Homework Statement


I am wondering, what happens to those photons ( all having same energy level) in a light beam when the photons don't have enough energy to release the electrons in the metal that are more tightly attracted?
Does the overall work function of the material decrease?


Homework Equations



KE= h*f- Workfunction

The Attempt at a Solution



At first glance, the eletrons in the material should become lessly attracted than before because when a light beam shines at an area, the temperature of that area increase.
However, there's a rule that states that frequency below the lowest frequency of the light beam will not release the ANY electron no matter how long you shine the beam. So base on this, the electrons shouldn't become less attracted.

But still, what happen to those electrons that don't have eneough energy to expell the electrons?
 
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kougou said:

Homework Statement


I am wondering, what happens to those photons ( all having same energy level) in a light beam when the photons don't have enough energy to release the electrons in the metal that are more tightly attracted?
Does the overall work function of the material decrease?


Homework Equations



KE= h*f- Workfunction

The Attempt at a Solution



At first glance, the eletrons in the material should become lessly attracted than before because when a light beam shines at an area, the temperature of that area increase.
However, there's a rule that states that frequency below the lowest frequency of the light beam will not release the ANY electron no matter how long you shine the beam. So base on this, the electrons shouldn't become less attracted.

But still, what happen to those electrons that don't have eneough energy to expell the electrons?

When the photon interacts with a free electron , but the energy is not enough to free the electron from the metal, the electron gains kinetic energy, so it will do its random motion inside the metal with higher speed. The electron collides with the vibrating atoms, imperfections or other electrons, and either re-radiates its extra energy as a photon (that is, part of the incident light is reflected) or transfers it to the vibrating atoms or to other electrons, so its extra energy is transferred to the whole metal. The metal becomes a bit warmer, then its transfers heat to the surroundings. So the energy of the absorbed photon will "heat up" the Universe at the end.

ehild
 

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