What is the work function of the metal?

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Homework Help Overview

The discussion revolves around determining the work function of a metal when exposed to light of a specific wavelength, resulting in the emission of photoelectrons. The context involves concepts from photoelectric effect and energy calculations.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between the energy of the incoming photons and the kinetic energy of the emitted electrons. Questions arise regarding the appropriate equations to use and the significance of the given wavelength.

Discussion Status

Some participants have provided guidance on the equations to consider, while others are exploring different interpretations of the problem. There is an ongoing examination of the calculations related to the work function and the energy of the electrons.

Contextual Notes

Participants note the importance of using the correct mass for calculations and the need for proper units in the final answer. There is also mention of the distinction between the photon energy and the excess energy of the electrons.

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Light of 300 nm wavelength strikes a metal plate, and photoelectrons are produced moving as fast of 0.002c. What is the work function of the metal?
 
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What have you tried so far? Please show what work you've done. We don't give out solutions here.
 
I don't know what equations to use. Do I have to use the moving speed to find the energy, but I don't know how to use that 300nm since it's not the cutoff wavelength.
 
The electrons have an "excess" energy: so the work function should equal the difference between the photon energy and the excess energy.
 
Should I use 0.5mv^2=hc/wavelength-work function, then what should I use for the mass in 0.5mv^2, the mass of an electron?
 
Yes, you use the mass of an electron.
 
So I have 3.108 for the answer of the work function
 
is that right?
 
Seems reasonable to me.
 
  • #10
Your answer should contain the correct unit, though!
 
  • #11
3.108eV
 
  • #12
okay, that sounds like the right order of magnitude.
 

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