The shoretest wavelength in Lyman series is 91.2 nm. The longest wavelength of the series is
The shoretest wavelength in Lyman series is 91.2 nm. The longest wavelength of the series is
A. 121.6 nm
B. 182.4 nm
C. 243. 4nm
D. 364.8 nm
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Correct Answer - A
The wavelength `(lambda)` of lines is given by
`" " (1)/(lambda)=R((1)/(1^(2))-(1)/(n^(2)))`
For Lyman seris, the shortest wavelength is for `n=oo` and longest is for n=2
`:. " " (1)/(lambda_(s))=R((1)/(1^(2)))" "....(i)`
`" " (1)/(lambda_(L))=R((1)/(1^(2))-(1)/(2^(2)))=(3)/(4)R" "....(ii)`
On dividing Eq. (ii) by Eq. (ii), we get `" " (lambda_(L))/(lambda_(s))=(4)/(3)`
Given `" " lambda_(s)=91.2 nm rArr lambda_(L)=91.2xx(4)/(3)=121.6 nm`
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