The shortest wavelength in the Lyman series is `911.6Å`. Then the longest wavelength in Lyman series is ......

Options

A. `1215Å`
B. `oo`
C. `2430Å`
D. `600Å`

Answer

A

Explanation

For Lyman series `(1)/(lamda)=R[(1)/(l^(2))-(1)/(n^(2))]`
`:.(1)/(lamda_(min))=R[(1)/(1^(2))-(1)/(oo^(2))]`
`:.(1)/(lamda_(min))=R" "......(1)`
`[:.(1)/(oo^(2))=0]`
For maximum wavelength n = 2,
`(1)/(lamda_(min))=R[(1)/(l^(2))-(1)/(2^(2))]`
`=R[(1)/(l)-(1)/(4)]`
`(1)/(lamda_(max))=(3R)/(4)" "......(2)`
`:.(lamda_(max))/(lamda_(min))=(R)/((3R)/(4))`
Taking ratio of equation (1) and (2),
`:.lamda_(max)=(4)/(3)xxlamda_(min)`
`=(4)/(3)xx911.6Å`
`=4xx303.9=1215.6Å`
`:.lamda_(max)=1215Å`
(Taking near by value in integer)