A sample consisting of Hydrogen atoms in the ground state is excited by monochromatic radiation of energy 12 . 75   e V . If we were to observe the emission spectrum of this sample, then the number of spectral lines observed, will be

Step-by-step solution

The energy of an electron of a hydrogen atom in the ground state is E 0 = - 13 . 6   eV The energy of incoming photon = 12 . 75   eV The energy of an electron in the excited state is - 13 . 6 n 2 = - 13 . 6 + 12 . 75 = - 0 . 85   eV ⇒ n 2 = 13 . 6 0 . 85 = 16 ⇒ n = 4 No. of spectral lines = n n - 1 2 = 6