A doubly ionized  Li2+ ion in ground state absorbs 91.8 eV of energy. The increase in angular momentum of electron is h= 6.63 × 10-4Js .

Z213.61-1n2 =91.8   here Z=3  and solving for n we get n=2  angular  momentum of electron in any orbit is nh2π so change in angular momentum h2π2-1=6.63×10-346.28=1.05 × 10-34