Why Does Kinetic Energy of Electron in Photoelectrics Follow Classical Approach?

In summary, the kinetic energy of an electron released from a metal when struck by a photon follows the classical approach rather than the relativistic formula. While this may be an approximation, it is still accurate for non-relativistic photoelectrons commonly observed in photoelectric experiments.
  • #1
Azmodan
4
0
Hello friends.

I was just wondering why in photoelectrics, the kinetic energy of an electron released from a certain metal after being struck by a photon follows the classical approach and not the relativistic. For example...

E_photon = (Planck_const)(frequency) = (Work function) + (1/2)(mass_electron)(u^2)

instead of

E_photon = (Planck_const)(frequency) = (Work function) + ((1 - ((u/c)^2)))^(-1)) - 1)(mass_electron)(c^2)

I've read several texts, including my university's text and Serway's text but the answer isn't really there. Thanks in advance!
 
Last edited:
Physics news on Phys.org
  • #2
Azmodan said:
I was just wondering why in photoelectrics, the kinetic energy of an electron released from a certain metal after being struck by a photon follows the classical approach and not the relativistic.

AFAIK all the photoelectric experiments that have ever been done have involved highly non-relativistic photoelectrons, so the classical formula works fine, but strictly speaking, it is an approximation and the relativistic formula is the strictly correct one.
 
  • #3
Cool, thanks Peter.
 

1. Why is the classical approach used to explain the kinetic energy of electrons in photoelectrics?

The classical approach is used because it provides a simple and intuitive explanation for the phenomenon. It is based on the principles of classical mechanics, which have been extensively studied and are well understood. Additionally, the classical approach can accurately predict the behavior of electrons in photoelectric experiments.

2. Is the classical approach the only way to understand the kinetic energy of electrons in photoelectrics?

No, the classical approach is not the only way to understand the kinetic energy of electrons in photoelectrics. Quantum mechanics also provides a more comprehensive and accurate explanation for this phenomenon. However, the classical approach is still used because it is easier to understand and provides a good approximation in many cases.

3. How does the classical approach explain the kinetic energy of electrons in photoelectrics?

The classical approach explains that when light shines on a metal surface, it transfers its energy to the electrons in the metal. This energy is then used by the electrons to overcome the binding forces of the metal atoms and escape from the surface, resulting in a flow of electrons or an electric current. The kinetic energy of the electrons is related to the energy of the incident light, and can be calculated using classical equations.

4. What are the limitations of the classical approach in explaining the kinetic energy of electrons in photoelectrics?

The classical approach has some limitations in explaining the kinetic energy of electrons in photoelectrics. It does not take into account the wave-like nature of light and electrons, and therefore cannot explain certain observations such as the photoelectric effect in different colors of light. It also cannot explain the discrete energy levels of electrons in atoms, which are predicted by quantum mechanics.

5. How does the classical approach compare to the quantum mechanical approach in explaining the kinetic energy of electrons in photoelectrics?

The classical approach and the quantum mechanical approach both provide explanations for the kinetic energy of electrons in photoelectrics, but they differ in their underlying principles. The classical approach is based on classical mechanics and treats electrons as particles, while the quantum mechanical approach is based on quantum mechanics and treats electrons as both particles and waves. The quantum mechanical approach is more accurate and can explain a wider range of observations, but the classical approach is still useful for providing a simple and intuitive explanation.

Similar threads

B What is m in Kinetic Energy? Relativistic mass or Rest mass?
    • Special and General Relativity
2
Replies
55
Views
3K
B How to relate relativistic kinetic energy and momentum
    • Special and General Relativity
Replies
4
Views
2K
B Questions about the relativistic kinetic energy expressions
    • Special and General Relativity
2
Replies
58
Views
4K
Photoelectric effect confusion
    • Introductory Physics Homework Help
2
Replies
35
Views
1K
I Question about the Photoelectric Effect and the Work Function of a Metal
    • Quantum Physics
Replies
5
Views
652
I Deriving formula for kinetic energy
    • Classical Physics
Replies
3
Views
565
I Kinetic Energy and Potential Energy of Electrons
    • Quantum Physics
Replies
15
Views
2K
I Photoelectric effect and Saturation Current
    • Quantum Physics
Replies
12
Views
749
I Kinetic Energy derivation assumption?
    • Mechanics
Replies
11
Views
980
I Energy Density in SR Energy-Momentum Tensor
    • Special and General Relativity
Replies
12
Views
1K

Hot Threads

Recent Insights

Back
Top