• # question_answer 6) The wave number of first line of Balmer series of hydrogen is $15200\text{ }c{{m}^{-1}}$ .The wave number of first Balmer line of $L{{i}^{2+}}$ion is A)  $15200\,c{{m}^{-1}}$                       B)  $60800\,c{{m}^{-1}}$C)  $76000\,c{{m}^{-1}}$                       D)  $136800\,c{{m}^{-1}}$

V for hydrogen like species $={{v}_{H}}\times {{Z}^{2}}=15200\times {{3}^{2}}=15200\times 9=136800c{{m}^{-1}}$