The ionisation potential of hydrogen atom is $$-$$13.6 eV. An electron in the ground state of a hydrogen atom absorbs a photon of energy 12.75 eV. How many different spectral lines can one expect when the electron make a downward transition?

Which of the following statements is correct?

Which of the following statement(s) is/are truc in respect of nuclear binding energy ?

(i) The mass energy of a nucleus is larger than the total mass energy of its individual protons and neutrons.

(ii) If a nucleus could be separated into its nucleons, an energy equal to the binding energy would have to be transferred to the particles during the separating process.

(iii) The binding energy is a measure of how well the nucleons in a nucleus are held together.

(iv) The nuclear fission is somehow related to acquiring higher binding energy.

If the potential energy of a hydrogen atom in the first excited state is assumed to be zero, then the total energy of n = $$\infty$$ state is,