Calculate ionisation potential of the electron in the first exited state of singly ionised Helium atom is given by ionisation of Hydrogen atom to be 13.6 eV.
Ans: According to Bohr,
Ionisation potential of an element = (ionisation potential of hydrogen)/ n2
We know for helium n=2
Hence IP of He = 13.6/ 22= 3.4 eV