In hydrogen spectrum the shortest wavelength in Balmer series is`lambda`. The shortest wavelength in Bracket series will be

Options

A. `2lambda`
B. `4lambda`
C. `9lambda`
D. `16lambda`

Answer

b

Explanation

Balmer series of hydrogen spectrum is ,`1/lambda=R[1/2^2-1/n_2^2]`
The shortest wvelength in Balmer series, `n_2=00`
`implies 1/lambda=R[1/2_2-1/oo^2]=R/4`
`implies R=4/lambda`
Bracket series of hydrogen spectrum is,`1/lambda=R[1/4^2-1/n^2]`
The shortest wavelength in Bracket series, `n_2=oo`
`1/(lambda')=R[1/4^2-1/oo^2]=R/16`
`implies 1/(lambda')=(4)/((lambda)/16)=1/(4lambda)`
`therefore lambda'=4lambda`