According to the definition of hydrogen emission spectrum where there is no external influence the hydrogen is in its ground state (electron in the box shell or level). To make hydrogen ionise, we must give energy so that the electron can move from the first level to the last. Measurement of the distance between the initial and non-end levels is called ionization power. By determining the frequency, we can determine the energy required at the first to last level (ionization point). From this effect, we can calculate the ionization power.