Question

The frequency of the first line in Lyman series in the hydrogen spectrum is $v$. What is the frequency of the corresponding line in the spectrum of doubly ionized Lithium ?

• A. $v$
• B. $3v$
• C. $9v$
• D. $27v$

Answer 1

The correct option is C $9v$

The frequency of the hymon series in the hydrogen spectrum is given by,

${\mho }_H=\frac{2{\pi }^{2}m{k}^2{e}^4{Z}^2}{h^3}(\frac{1}{1^2}-\frac{1}{n^2})$

Therefore, for hydrogen z=1,

${\mho }_H=\frac{2{\pi }^{2}m{k}^2{e}^4}{h^3}(\frac{1}{1^2}-\frac{1}{n^2})=1$

Now, for doubly ionized lithium z=3,

${\mho }_L=\frac{2{\pi }^{2}m{k}^2{e}^4\left(9\right)}{h^3}(\frac{1}{1^2}-\frac{1}{n^2})=9V$