Einstein's photoelectric equation is given by_______________?
Correct answer: C. 1/2 mvmax2=hf-Φ
- A. 1/2 mvmax2=hf+Φ
- B. 1/2 mvmax2-hf = Φ
- C. 1/2 mvmax2=hf-Φ
- D. All of above are correct
Explanation
Einstein's photoelectric equation is hf = Φ + Kmax, so Kmax = 1/2 mvmax^2 = hf - Φ. The work function must be subtracted because part of the photon energy releases the electron from the metal. Students may choose a by adding the work function, which incorrectly treats emission energy as an extra gain rather than an energy cost.
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About Photons and the Particle Model of Light
The particle model treats light as photons with energy E equals hf and momentum related to wavelength. Questions involve the photoelectric effect, work function, threshold frequency, stopping potential and photon energy, while distinguishing particle behaviour from the wave description of interference and diffraction.
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