Q.

In hydrogen spectrum, the shortest wavelength in the Balmer series is λ. The shortest wavelength in the Bracket series is          [2023]

1 9λ  
2 16λ  
3 2λ  
4 4λ  

Ans.

(4)

Shortest wavelength in Balmer series when transition of electron from  to n=2

1λ=R(122-12)

1λ=R22=R4                                             ...(i)

For Brackett series,

1λ'=R(1)2(142-12)=R(142)=R16                ...(ii)

Divide (i) by (ii), we get

λ'λ=164=4λ'=4λ