Einstein's Photoelectric Equation and its graph

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Discussion Overview

The discussion revolves around Einstein's photoelectric equation and its graphical representation, specifically focusing on the relationship between the kinetic energy of emitted photoelectrons and the frequency of incident radiation. Participants explore the implications of the equation and the characteristics of the resulting graph.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that the slope of the graph depends on the nature of the metal used.
  • Another participant requests the formulation of Einstein's photoelectric effect equation to clarify the discussion.
  • Several participants express familiarity with the equation and its components, indicating a shared understanding of the basic concepts.
  • There is a discussion about the mathematical representation of the relationship, comparing the photoelectric effect equation to the general equation of a straight line.
  • One participant emphasizes the importance of understanding the mathematics behind the graph without providing detailed explanations.

Areas of Agreement / Disagreement

Participants generally agree on the formulation of the photoelectric effect equation, but there is some contention regarding the specifics of the graph and the factors influencing its slope. The discussion remains unresolved regarding the exact dependencies of the slope on the metal used.

Contextual Notes

Some assumptions about participants' mathematical knowledge are made, and there is a lack of clarity on how different metals might affect the slope of the graph.

Bloopy
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According to the equation, the graph of kinetic energy of emitted photoelectrons from a metal vs the frequency of incident radiation gives a straight line.

My doubt is, what factors does the slope of this line depend on? I think it depends on the nature of metal used. Correct me if I am wrong.
 
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Hi Bloopy, :welcome:
Bloopy said:
According to the equation,
It looks as if you know which equation that is. Can you write it up in a post ?
 
I know this.
 

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Bloopy said:
I know this.

This is really not an "equation". So let's start all over again. Can you write down the Einstein's photoelectric effect equation?

Zz.
 
Bloopy said:
I know this.
And what do you think of the mathematical description in the Wikipedia lemma right beside this picture ?
 
ZapperZ said:
Can you write down the Einstein's photoelectric effect equation?

Energy supplied=Work Function + Kinetic Energy
 
Bloopy said:
Energy supplied=Work Function + Kinetic Energy

I am not quite sure why you are being a bit difficult, or if you don't quite know what you are doing.

So, if I write this:

Ek = hf - φ

where Ek is the maximum kinetic energy of the photoelectrons, h is the Planck constant, f is the frequency of light, and φ is the work function, do you understand that this is the photoelectric effect equation, similar to what you wrote, or do you need an explanation for this?

Zz.
 
ZapperZ said:
or do you need an explanation for this?
I am on the same page as you
 
Bloopy said:
No, I am on the same page

Not sure what page you're on, but OK.

Now, I will make the assumption that you know the mathematics for the equation of a straight line, i.e.

y = mx + b

so, I will not explain the meaning of that equation (this is the math that you should already know by the time you tackle this physics).

The graph you referred to in your original post is a graph of Ek versus f, i.e. Ek plotted in the vertical axis, and f in the horizontal axis. Make a visual identification of these two equations:

y = mx + b
Ek = hf - φ

If you identify

y→Ek

and

x→f

then what corresponds to the slope of the line? As a bonus, what corresponds to the y-intercept of the line?

Zz.
 
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