In order to determine the value of `E_(0)`, a scienctist shines photons (''light particles '')of various energies at a cloud of atomic hydrogen. Most of the hydrogen atom occupy transition through that cloud : see figure is a graph of part of the scientist's data, showing the idensity of the transmitted light as a function of the photon energy. A hydrogen atom's electron is likely to obsorb a photon only if the photon gives the electron enough energy to knock it into a higher shell.

According to this experiment , what is the approximate value of `E_(0)`?