As the electron in Bohr orbit of hydrogen atom passes from the state $n=2$ to $n=1$, the kinetic energy $K$ and potential energy $U$ changes as

Which of the following atoms has the lowest ionisation potential ?

Let the potential energy of hydrogen atom in the ground state be regarded as zero. Then the potential energy in the first excited state will be

As per Bohr model, the minimum energy (in $eV$) required to remove an electron from the ground state of doubly ionised $Li$ atom$(Z=3)$  is