Photoelectric Effect and stopping potential

  • Thread starter Turion
  • Start date
  • #1
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Homework Statement



When 445 nm light strikes a certain metal surface, the stopping potential is 70% of that which results when 410 nm light strikes the same metal.

Homework Equations





The Attempt at a Solution



$$P=0.7P'\\ \frac { nE }{ t } =\frac { 0.7nE' }{ t } \\ \frac { hc }{ λ } =\frac { 0.7hc }{ λ' } \\ \frac { λ' }{ λ } =0.7$$
 

Answers and Replies

  • #2
662
307
And the question is???
Oh and you are neglecting the work function of the metal- I think
 
  • #3
143
2
Opps. I didn't realize the question was cut off.

Here's the second part:

Based on this information and the table given in the textbook, identify the metal.

Basically, what is required is to calculate the work function.

A: work function 2.23 eV. Potassium.
 
  • #4
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Show your effort please. As suggested, did you take the work function into account? Retry the problem.
 

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