In the Bohr model of the hydrogen atom, the electron revolves around the nucleus under the influence of electrostatic attraction. For a system bound by an inverse square law force (like electrostatic or gravitational force), the relationship between Total Energy ($E$), Kinetic Energy ($K$), and Potential Energy ($U$) is given by the virial theorem: $E = -K$ $U = 2E$

Given the total energy of the first excited state is $E = -3.4 \text{ eV}$.

To find the Kinetic Energy ($K$): $K = -E$ $K = -(-3.4 \text{ eV})$ $K = +3.4 \text{ eV}$

Thus, the kinetic energy is equal in magnitude to the total energy but is always positive .