What Is the Wavelength of the Emitted Photon If an Electron

Multiple Choice

What is the wavelength of the emitted photon if an electron in the hydrogen atom makes a transition from the $n = 7$ state to the $n = 2$ state? $\left( c = 3.00 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } , h = 6.626 \times 10 ^ { - 34 } \mathrm {~J} \cdot \mathrm { s } , 1 \mathrm { eV } = \right.$ $1.60 \times 10 ^ { - 19 } \mathrm {~J}$ )

A) $796 \mathrm {~nm}$
B) $398 \mathrm {~nm}$
C) $4480 \mathrm {~nm}$
D) $199 \mathrm {~nm}$
E) $365 \mathrm {~nm}$