Quick question about PhotoElectric Effect

In summary, when a light beam with photons of the same energy level does not have enough energy to release electrons in a metal with a high work function, the electrons gain kinetic energy and increase their random motion within the metal. This causes collisions with other particles and results in heat being transferred to the surroundings. Therefore, the absorbed photon's energy is ultimately transferred to the rest of the universe as heat.
  • #1
kougou
82
0

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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  • #2
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
 

1. What is the PhotoElectric Effect?

The PhotoElectric Effect is a phenomenon in which electrons are emitted from a material when it is exposed to electromagnetic radiation, such as light.

2. Who discovered the PhotoElectric Effect?

The PhotoElectric Effect was first observed by Heinrich Hertz in 1887, but it was Albert Einstein who explained the underlying physics and won the Nobel Prize in Physics for his work in 1921.

3. How does the PhotoElectric Effect work?

When a photon of light hits a material, it transfers its energy to an electron, giving it enough energy to escape the binding forces of the material and become a free electron.

4. What are the applications of the PhotoElectric Effect?

The PhotoElectric Effect is used in many technologies, such as solar panels, photodiodes, and digital cameras. It is also the basis for the function of photoelectric cells and photocells in light sensors.

5. What factors affect the PhotoElectric Effect?

The intensity and frequency of the incident light, as well as the properties of the material, such as its work function and band gap, can all affect the PhotoElectric Effect.

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