The ratio of the longest to the shortest wavelength lines in the Balmer series is

Options

A. 1.1
B. 8.8
C. 1.8
D. 8.1

Answer

C

Explanation

For longest wavelength of Balmer series p=2 and n=3
`:. 1/lambda_(1)=R [1/4-1/9]`
`:. Lambda_(1)=36/(5R)` ...(i)
For shortest wavelength of Balmer series p=2 and `n=oo`.
`:. 1/lambda_(2)=R[1/4-1/oo]`
`:. Lambda_(2)=4/R` ...(ii)
`lambda_(1)/lambda_(2)=36/(5R)xxR/4`
`=36/20=1.8`.