Atoms and Nuclei

Consider a hydrogen-like ionized atom with atomic number Z with a single electron. In the emission spectrum of this atom, the photon emitted in the n=2 to n=1 transition has energy 74.8eV higher than the photon emitted in the n=3 to n=2 transition. The ionization energy of the hydrogen atom is 13.6eV. The value of Z is .