How far from the lightbulb can you stand to see it? photon problem

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SUMMARY

The discussion focuses on calculating the distance from a lightbulb at which a person can perceive photons, specifically addressing a homework problem involving photon density. The equation E=hf is referenced, indicating the relationship between energy and frequency of photons. Participants suggest modeling the distribution of photons over a spherical surface area at distance R from the light source, ultimately leading to an expression that equates photon density to the specified number of photons per square meter at the pupil's area. This approach allows for solving the distance R effectively.

PREREQUISITES
  • Understanding of photon energy and frequency (E=hf)
  • Basic knowledge of geometry, specifically surface area of a sphere
  • Familiarity with concepts of light intensity and photon distribution
  • Ability to solve algebraic equations for distance
NEXT STEPS
  • Research the concept of photon density and its implications in optics
  • Learn about the surface area calculations for spheres in geometry
  • Explore the relationship between light intensity and distance from a point source
  • Study the principles of light perception in human vision
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Students in physics, educators teaching optics, and anyone interested in the practical applications of light and photon behavior.

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Homework Statement



http://www.screencast.com/users/trinhn812/folders/Jing/media/23298f1b-2ef4-4cdf-8b7a-58c9be07335a

Homework Equations


E=hf


The Attempt at a Solution


I'm not even sure how to get the distance for this problem.
 
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Looks like an interesting problem, okgo.
And you have a good start.
Those photons are spread over the surface area of a sphere at distance R from the light bulb. You should be able to write an expression for the number of photons per square meter at radius R. Equate that to the specified 20 per (area of pupil).
Then you can solve for R.
 

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