Answer
$E_1 = -13.6~eV$
Work Step by Step
We can calculate the value of $E_1$:
$E_1 = \frac{-m_e~k^2~e^4}{2\hbar^2}$
$E_1 = \frac{-(9.1\times 10^{-31}~kg)(9.0\times 10^9~N~m^2/C^2)^2(1.6\times 10^{-19}~C)^4}{(2)(1.0546\times 10^{-34}~J~s)^2}$
$E_1 = (-2.1717\times 10^{-18}~J)(\frac{1~eV}{1.6\times 10^{-19}~J})$
$E_1 = -13.6~eV$
