In a H-like species there are two energy levels A & B above the ground state having principal quantum numbers of $n_1\&n_2$ respectively. A sample of this H-like species has all atoms/ions in excited levels A or B only and other energy level. Energy of level B is greater than that of level A and a total of 15 different lines are emitted from this sample on returning of ground state out of which 6 lines are emitted due to electronic transitions between the levels $n_1\&n_2$ only. Also energy difference between  $n_1\&n_2,E{n}_2-E{n}_1=4.53eV$