The ratio of wavelength of the lest line of Balmer series and the last line Lyman series is:

Options

A. `1`
B. `4`
C. `0.5`
D. `2`

Answer

B

Explanation

For last line of Balmer `:n_(1) = 2` and `n_(2) = oo`
`(1)/(lambda_(B)) = RZ^(2) [(1)/(n_(1)^(2)) - (1)/(n_(2)^(2))] = R(1)^(2)[(1)/(2^(2)) - (1)/(oo^(2))]`
`lambda_(B) = (4)/(R ) …..(i)`
For lest line of Lyman series: `n_(1) = 1` and `n_(2) = oo`
`(1)/(lambda_(L)) = RZ^(2) [(1)/(n_(1)^(2)) - (1)/(n_(2)^(2))] = R(1)^(2)[(1)/(2^(2)) - (1)/(oo^(2))]`
`lambda_(L) = (1)/(R ) .....(ii)`
`(lambda_(B))/(lambda_(L)) = ((4//R))/((1//R)) = 4`