Ball emerges with ke kick energy mgh energy needed

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Unformatted text preview: ll and out. mgh for highest electron analogous to work funcHon. h Kick energy. Top ones get out, boXom don’t. Harder kick (shorter wavelength light), more get out. electrons metal Kicker analogy: a ball in a pit Light like a Kicker… Puts in energy. All concentrated on one ball/electron. Blue kicker always kicks the same, and harder than red kicker always kicks. Ball emerges with: KE = kick energy - mgh energy needed to get most energeHc electron out of pit (“work funcHon”) h h sodium- easy to kick out small work funcHon ⇔ shallow pit plaHnum, hard to kick out large work funcHon ⇔ deep pit If photon has enough energy, electron emerges with: KE = photon energy – work funcHon Photon… Puts in kick of energy energy needed to kick highest electron out of metal. “WORK FUNCTION” (φ) Each photon has: Energy =hf = Planks constant * Frequency (Energy in Joules) (Energy in eV) E=hf=(6.626*10- 34 J- s)*(f s- 1) E=hf= (4.14*10- 15 eV- s)*(f s- 1) E=hc/λ = (1.99*10- 25 J- m)/(λ m) E= hc/λ = (1240 eV- nm)/(λ nm) IniHal KE of electron = Ephoton - energy needed to kick as it comes out of metal electron out of metal Depends on type of metal. Typical energies Photon Energies: Each photon has: Energy = Plank’s constant * Frequency (Energy in Joules) (Energy in eV) E=hf=(6.626*10- 34 J- s)*(f s- 1) E=hf= (4.14*10- 15 eV- s)*(f s- 1) E=hc/λ = (1.99*10- 2...
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This document was uploaded on 02/26/2014 for the course PHYSICS 2130 at Colorado.

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