Q.

The ratio of wavelength of spectral lines Hα and Hβ in the Balmer series is x20. The value of x is ________.            [2023]
 


Ans.

(27)

1λ=R[1n12-1n22]  for H-atom

For Balmer series, n1=2

1λ=R[14-1n22]

For Hα, n2=3 and Hβ, n2=4

1λHα=R[14-19]=5R36

1λHβ=R[14-116]=3R16

1λHα1λHβ=5R363R16

λHαλHβ=2720=x20x=27