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An early model for an atom considered it to have a positively chargedpoint nucleus of charge Ze , surrounded by a uniform density of negative charge up to a radius R . The ato as a whole is neutral . For this model what is the electric field at a distance 's' from the nucleus ? |
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Answer» Charge on nucleus is =+Ze total negative charge =−Ze(∵ atoms is electrical neutral) Negative charge DENSITY, ρ=volumecharge=34πR3−Ze i.e., ρ=−43πR3Ze...(i) Consider a Gaussian surface with radius r By Gauss's theorem ϕ=E(r)×4πr2=ε0q....(II) Charge ENCLOSED by Gaussian surface q′=Ze+34πr3ρ=Ze−ZeR3r3 [Using (i)] From (ii) E(r)=4πε0r2q′=4πε0r2Ze−ZeR3r3 |
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