Q: Find the kinetic energy, potential energy and total energy in first and second orbit of hydrogen atom if

potential energy in first orbit is taken to be zero.

Sol: E_{1} = -13.60 eV ; K_{1} = -E_{1} = 13.60 eV

U_{1} = 2 E_{1} = -27.20 eV E_{2} = -3.40 eV K_{2} = 3.40 eV and U_{2} = -6.80 eV

Now, U_{1} = 0, i.e., potential energy has been increased by 27.20 eV. So, we will increase U and E in all

energy status by 27.20 eV while kinetic energy will remain unchanged .

Hence K (eV), U(eV), E(eV)

First orbit are 13.6 , 0 , 13.6

In second orbit 3.40 , 20.40 , 23.80