Estimate value for Planck's Constant? Please help hopeless A level student

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SUMMARY

The discussion focuses on estimating Planck's constant using the photoelectric effect with potassium. The incident light wavelengths of 5.5 x 10-7 m and 5.0 x 10-7 m are analyzed, with the latter resulting in electrons emerging with an energy of 3.62 x 10-20 J. The relationship between photon energy and wavelength is established through the equation E = hc/λ, leading to the formula ΔE = h c / (Δλ) for calculating Planck's constant. By substituting the provided data into this equation, a value for h can be derived.

PREREQUISITES
  • Understanding of the photoelectric effect
  • Familiarity with the equation E = hc/λ
  • Knowledge of work functions in quantum physics
  • Basic algebra for solving equations
NEXT STEPS
  • Calculate Planck's constant using the derived formula ΔE = h c / (Δλ)
  • Explore the concept of work function in detail
  • Study the implications of the photoelectric effect in modern physics
  • Learn about the historical significance of Planck's constant in quantum mechanics
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Students studying quantum physics, particularly those preparing for A-level examinations, as well as educators looking for practical examples of the photoelectric effect and Planck's constant.

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Homework Statement



A clean surface of potassium in a vacuum is irradiated with light of wavelength 5.5 x10 -7 m and electrons are found just to emerge, but when light of wavelength 5.0 x 10 -7 m is incident, electrons emerge with energy 3.62 x 10-20 J. Estimate a value for Planck's constant.

I understand the basics like finding work functions and Einstein's equation, but I haven't got a clue with this one. This is an emergency!
 
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Once the energy of the incident photons is sufficient to overcome the work function, any additional energy is converted into the KE of the electrons. The energy of a photon is E = hc/\lambda.

We can therefore estimate h from the data you have by writing

\Delta E = h c / (\Delta\lambda).

Solve for h, and substitute your data.
 

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