For potassium metal, the work function $\Phi$ (the minimum energy needed to eject an electron from the metal surface) is 3.68 × 10^-19 J. Which is the longest wavelength of the following which could excite photoelectrons? A) 550. nm B) 500. nm C) 450. nm D) 400. nm E) 350. nm

Question

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The energy of a photon is given by E = hc/λ. To eject an electron, this energy must be at least equal to the work function. Using the given work function, the longest wavelength that can excite photoelectrons is calculated to be approximately 500 nm.

For Potassium Metal, the Work Function Φ\PhiΦ (The Minimum Energy Needed to Eject an Electron from the Needed

For Potassium Metal, the Work Function $\Phi$ (The Minimum Energy Needed to Eject an Electron from the Needed