What is the ionisation energy of hydrogen in eV?

Ionization energy of hydrogen is

Light from a dicharge tube containing hydrogen atoms falls on the surface of sodium.The kinetic energy of the fastest electrons emitted from sodium is 0.73 eV.The work function for sodium is 1.82 eV.find the recoil speed of the emitting atom assuming it to be at rest before the transmition.(Ionisation energy of hydrogen is 13.6 eV).

A neutron beam of energy E scatters from atoms on a surface with a spacing d=0.1nm. The first maximum of intensity in the reflected beam occurs at theta=30 . What is the kinetic energy E of the beam in eV?

The total energy of an electron in the first excited state of the hydrogen atom is about-3.4ev What is the kinetic energy of the electron in this state?

The total energy of an electron in the first excited state of the hydrogen atom is about-3.4ev What is the potential energy of the electron in this state?

The total energy of an electron in the first excited state of the hydrogen atom is about -3.4 eV. (A) What is the kinetic energy of the electron in this state? (B) What is the potential energy of the electron in this state? (C) Which of the answers above would change if the choice of the zero of potential energy is changed?

The ground state energy of hydrogen atom is -13.6eV. what is the potential energy of the electron in this state?