Explain Photoelectric Effect: Potential, Formula & Voltage

Click For Summary

Discussion Overview

The discussion revolves around the photoelectric effect, specifically focusing on the concept of stopping potential, the formula involving electron charge and voltage, and the energy transfer during photon absorption. Participants explore theoretical aspects, clarify terminology, and examine the implications of energy conservation in this context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire about the definition of stopping potential and the formula e × Vs, questioning whether V represents voltage.
  • One participant explains that when a photon is absorbed, part of its energy frees the electron, with the remaining energy converted to kinetic energy, linking this to the concept of stopping potential.
  • A later reply questions the accuracy of the initial explanation, suggesting that the leftover energy transferred to the electron may vary and that other processes could affect energy transfer.
  • Another participant references a textbook, noting that the maximum kinetic energy of the freed electron is equal to the leftover photon energy, indicating potential complexities in energy transfer.
  • Further discussion highlights that the energy required to free an electron is not uniform, as it depends on how "deeply buried" the electron is within the material, affecting the maximum kinetic energy post-ejection.

Areas of Agreement / Disagreement

Participants express differing views on the energy transfer process during the photoelectric effect, with some asserting a fixed relationship between photon energy and kinetic energy, while others suggest variability and additional processes at play. The discussion remains unresolved regarding the nuances of energy transfer.

Contextual Notes

Participants reference different educational materials, indicating potential variations in the treatment of the photoelectric effect across sources. There are unresolved questions about the assumptions underlying energy transfer and the role of other processes that may influence the kinetic energy of freed electrons.

Gajan1234
Messages
46
Reaction score
2
Can someone explain what is stopping potenial is and can explain the formula : e × Vs. Does the v stand for voltage
 
Physics news on Phys.org
Gajan1234 said:
Can someone explain what is stopping potenial is and can explain the formula : e × Vs. Does the v stand for voltage
Can you show us the reading you've been doing about this please? Thanks. :smile:
 
When a photon is absorbed some of its energy is used to free the electron and what is left over is given to the freed electron as kinetic energy. The stopping potential slows the electron down and if the potential is high enough the electrons won't make it to the detector. The value of the potential at which this happens occurs when the work done by the electric field is equal to the kinetic energy. This value is eV xS, so yes V is the potential (or voltage difference).
 
Jilang said:
When a photon is absorbed some of its energy is used to free the electron and what is left over is given to the freed electron as kinetic energy.

Is that exactly true? Or is there a range of possible leftover energy transferred from the photon to the electron as kinetic, from 0 up to the entire leftover energy? I don't have the textbook with me, but in Serway's "Modern Physics", he mentions a maximum kinetic energy for the freed electron being equal to the leftover photon energy, which implies there are probably other processes which might take away said energy.
 
Jilang said:
When a photon is absorbed some of its energy is used to free the electron and what is left over is given to the freed electron as kinetic energy.
cryora said:
in Serway's "Modern Physics", he mentions a maximum kinetic energy for the freed electron being equal to the leftover photon energy, which implies there are probably other processes which might take away said energy.
In the (over)simplified treatment of the photoelectric effect that you commonly find in introductory textbooks like that, the "energy used to free the electron" is not the same for each electron. Crudely and simplistically speaking, think of it as reflecting how "deeply buried" the electron was in the material. A certain minimum energy is needed to free the electron, corresponding to a maximum kinetic energy after ejection.
 
  • Like
Likes   Reactions: cryora

Similar threads

High School Photoelectric and summation of photons energy
  • · Replies 8 ·
Replies
8
Views
771
High School Photoelectric phenomenum can only be proved as a particle effect?
  • · Replies 5 ·
Replies
5
Views
2K
High School Why is there now evidence of a lag time in the photoelectric effect?
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad Photoelectric effect: Saturation voltage
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Photoelectric effect and Saturation Current
  • · Replies 12 ·
Replies
12
Views
2K
Undergrad Some questions about the photoelectric experiment
  • · Replies 13 ·
Replies
13
Views
2K
High School Planck-Einstein relation and the Photoelectric Effect
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Ejection of Only one electron by a Photon in the Photoelectric effect
  • · Replies 5 ·
Replies
5
Views
3K
Graduate Photoelectric effect: V classically independent of intensity
  • · Replies 9 ·
Replies
9
Views
4K
Graduate Is Chapter 5's Approach to the Photoelectric Effect Unique in QFT Literature?
  • · Replies 5 ·
Replies
5
Views
2K