Answer
-0.544 eV
Work Step by Step
Use the angular momentum to find the quantum number n, from equation 27-11.
$$L=n\frac{h}{2\pi}$$
$$n=\frac{2\pi L}{h}$$
$$n=\frac{2\pi (5.273\times10^{-34}kg \cdot m^2/s)}{6.626\times10^{-34}J \cdot s}=5$$
Now find the energy using equation 27–15b with Z = 1 and n = 5.
$$E_{n}=\frac{-13.6eV(Z^2)}{n^2}$$
$$E_{n}=\frac{-13.6eV(1^2)}{5^2}=-0.544eV$$