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Hydrogen gas in the atomic state is excited to an energy level such tht the electrostatic potential energy of H-atom becomes `-1.7 eV`. Now, a photoelectric plate having work function w=2.3 eV is exposed to the emission spectra of this gas. Assuming all the transitions to be possible, find the minimum de-Broglie wavelength of the ejected photoelectrons. |
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Answer» Correct Answer - C `U = - 1.7 eV` `:. E = (U)/(2) =- 0.85 eV = (-13.6)/(n^2)` `:. N =4 ` Ejected photoelectron will have minimum de-Broglie wavelength corresponding to transition from n = 4 to n=1. `Delta E = E_4 -E_1 =- 0.85 - (-13.6)` = 12.75 eV `K_(max) = DeltaE - W = 10.45 eV` `:. lambda = sqrt((150)/(10.45)) Å` (for an electron)` = 3.8 Å |
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