(a)Find the wavelength of the radiation required to excited the electron is `Li^(++)` from the first to the third Bohr orbit (b) How many spectral lines are observed in the emission spectrum of the above excited system?
A. `108.8eV,3`
B. `13.6eV,4`
C. `54.4eV,2`
D. `10.2eV,3`