So I have the equation to find the energy in an infinite wellâ€¦

[tex] \[
\begin{array}{l}
E_n = n^2 \frac{{\pi ^2 (\hbar c)^2 }}{{2mc^2 L^2 }} \\
L = 2*10^3 nm \\
m = 5.11*10^5 eV \\
\hbar c = 197.33eV*nm \\
\end{array}
\][/tex]

Using this, I find n=1 to equal 9.40*10^-8 eV

The book says im good there.

The problem is when I have to find the second energy level. I figured you use n=2 which means its just 2^2 or 4 times the energy but the book says its just 2 times the energy of the first energy level. What am I not understanding here?