BITSAT 2019 Slot 2 Solved Paper

Given, total energy given to electron in third orbit,
E=12eV
Energy of third orbit of H -atom,
E′=

−13.6

n2

=

−13.6

32

=−1.51eV
lonisation energy of electron of third orbit, E"=−E′
=−(−151eV)⇒E"=151eV
Hence, final energy of electron when it comes out of H-atom from third orbit
EF=E−E"
=12−1.51=10.49eV