Atomic Structure: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Atomic Structure. Understanding the underlying formula is key to arriving at the correct answer below:

The total energy in the first excited state ($n=2$) is $E_2 = -13.6/2^2 = -3.4 eV$. Since kinetic energy $K = -E_n$, the kinetic energy in the first excited state is $3.4 eV$.