If lambda is the wavelength of hydrogen atom from the transition `n=3 to n=1`,then what is the wavelength for doubly ionised lithium ion for same transition?

Options

A. `(lambda)/(3)`
B. `3lambda`
C. `(lambda)/(9)`
D. `9lambda`

Answer

C

Explanation

For hydrogen atom, wavelength corresponding to the given transition.
`(1)/(lambda)=R[(1)/(1^2)-(1)/(3^2)]` ........(i)
`(1)/(lambda')=RZ^2[(1)/(1^2)-(1)/(3^2)]`.....(ii)
From (i) and (ii), we get
`(lambda')/(lambda)=(1)/(Z^2) or lambda'=(lambda)/(9)`