An energy of 13.6 eV is needed to ionise an electron from the ground state of a hydrogen atom.Selecting the longest wavelength that will work from those given below, what wavelength is needed if a photon accomplishes this task?
A)60 nm
B)80 nm
C)70 nm
D)90 nm
E)40 nm

Question

Quizplus · Accepted Answer

The energy of a photon is given by E = hc/λ. To ionize the electron, the energy must be at least 13.6 eV. The longest wavelength corresponds to the lowest energy photon that can still ionize the electron. Converting 13.6 eV to wavelength using the formula, the longest wavelength that can ionize the electron is approximately 91.2 nm. Therefore, 90 nm is the longest wavelength from the given options that can accomplish this task.

An Energy of 13