Which element has a hydrogen like spectrum whose lines have wavelength one fourth of atomic hydrogen ?A. `He^(+)`B. `Li^(2 +)`C. `Be^(3 +)`D. `B^(4 +)`

Which element has a hydrogen like spectrum whose lines have wavelength

1.	Which element has a hydrogen like spectrum whose lines have wavelength one fourth of atomic hydrogen ?A. `He^(+)`B. `Li^(2 +)`C. `Be^(3 +)`D. `B^(4 +)`
Answer» Correct Answer - A (a) `(1)/(lamda_H) = R xx 1^2 ((1)/(n_1^2) -(1)/(n_2^2))` ....(i) `(1)/(lamda_X) = RZ^2 ((1)/(n_1^2) -(1)/(n_2^2))` ....(ii) Dividing equation (i) by equation (ii), we get =`(lamda_x)/(lamda_H) = (1)/(Z^2)` `(1)/(4) = (1)/(Z^2)` `Z = 2 (He^+)`.

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Which element has a hydrogen like spectrum whose lines have wavelength one fourth of atomic hydrogen ?A. `He^(+)`B. `Li^(2 +)`C. `Be^(3 +)`D. `B^(4 +)`

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