InterviewSolution
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InterviewSolution
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The frequency of light emitted for the transition `n = 4` to `n =2` of `He^+` is equal to the transition in `H` atom corresponding to which of the following ?A. `n = 3 "to" n = 1`B. `n = 2 "to" n = 1`C. `n = 3 "to" n = 2`D. `n = 4 "to" n = 3` |
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Answer» Correct Answer - B (b) `Delta E = hu = (2 pi^2 mZ^2 e^4 k^2)/(h^2) [(1)/(n_1^2)-(1)/(n_2^2)]` If electron falls from `n_2 - "level to" n_1 - "level"` `:.` In `He^+, "for" n_2 = 4 "to" n_1 = 2 transition` `v_(He^+) = "constant" (4) [(1)/(2^2) -(1)/(4^2)][because Z_(He^2) = 2]` =`"constant" xx 4 [(3)/(16)] = (3)/(4) xx "constant"` `v(H) = "constant" (1) 2 [(1)/(n_1^2) - (1)/(n_2^2)]` =`"constant" xx [(1)/(n_1^2) - (1)/(n_2^2)]`. (a) For `n_2 = 3` and `n_1 = 1` `v(H) = "constant" [(1)/(1) -(1)/(9)]` =`(8)/(9) xx "constant" ne (3)/(4) xx "constant"` (b) For `n_2 = 2` and `n_1 = 1` `v(H) = "constant" xx [(1)/(1) -(1)/(4)]` =`(3)/(4) xx "constant" = v(He^+)` ( c) For `n=3` and `n_1 = 2` `v(H) = "constant" xx [(1)/(2^2) -(1)/(3^2)]` =`(5)/(36) xx "constant" ne v(He^+)` (d) For `n_2 = 4` and `n_1 = 3` `v(H) = "constant" xx [(1)/(3^2) - (1)/(4^2)]` =`(7)/(144) xx "constant" ne v(He^+)`. |
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