The total energy of eletcron in the ground state of hydrogen atom is `-13.6 eV`. The kinetic enegry of an electron in the first excited state is

Explanation

The energy of electorn in hydrogen atom when it revolves in nth orbits is ,
`E=(-13.63)/( n^(2)) eV`
In the ground state, n=1
` :. " " E=(-13.6)/(1^(2))=-13.6 eV`
For n=2, `" " E=(-13.6)/(2^(2))=-3.4 eV`
So kinetic, energy of electron in the first excited state i.e., for n=2 is , kinetic energy =-(total energy),
`K=-E=-(-3.4)=3.4 eV`