The ground state energy of hydrogen atom is -13.6 eV. When its electron is in the first excited state, its excitation energy is

Excitation energy is defined as the energy required to take the electron from ground level orbit to any higher order orbit (i.e., n = 2,3, 4...).Given, ground state energy of hydrogen atom E1 = -13'6 eVEnergy of electron in first excited state (i.e., n = 2)E2=−13.622eVTherefore. excitation energyΔE=E2−E1=−13.64−−136=−3.4+13.6=10.2eV