InterviewSolution
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InterviewSolution
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The ratio of the frequency corresponding to the third line in the Lymas series of hydrogen atomic spectrum to that of the first line in Balmer series of `Li^(2+)` spectrum isA. `(4)/(5)`B. `(5)/(4)`C. `(4)/(3)`D. `(3)/(4)` |
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Answer» Correct Answer - D For Lyman series, `n_(1) = 1`. For 3rd line of Lyman series `n_(2) = 4` For hydrogen, Z = 1. Hence, `v_(H) = (c)/(lamda) = c R_(H) Z^(2) ((1)/(n_(1)^(2)) - (1)/(n_(2)^(2)))` `= c R_(H) (1)^(2) ((1)/(1) - (1)/(4^(2))) = (15)/(16) R_(H.c)` for lithium, Z = 3 For 1st line of Balmer series, `n_(1) = 2, n_(2) = 3` `:. v_(Li) = c.R_(H) (3)^(2) ((1)/(2^(2)) - (1)/(3^(2)))` `= c.R_(H) xx 9 xx (5)/(36) =(5)/(4) c.R_(H)` `:. (v_(H))/(v_(Li)) = ((15//16) c R_(H))/((5//4) c R_(H)) = (15)/(16) xx (4)/(5) = (3)/(4)` |
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