Question

The total energy of hydrogen atom when electron is in the first excited state is about $-3.4eV$. The kinetic energy and potential energy of the electron in this state respectively are

• A. $3.4eV-3.4eV$
• B. $-3.4eV,-6.8eV$
• C. $3.4eV,-6.8eV$
• D. $6.8eV,-3.4eV$

Answer 1

The correct option is C $3.4eV,-6.8eV$

We know
$\text{Total Energy}=-\text{Kinetic Energy}=\frac{\text{Potential Energy}}{2}$
Given total energy $=-3.4eV$
Hence
Kinetic energy = - Total energy = $3.4eV$
and
Potential energy = $2\times$Total energy = $-6.8eV$