Shows the energy-level diagram of hydrogen like imaginary element X. (hc=1242 eV-nm)

Options

A. The ionization energy of Element X is 4eV
B. An atom in the ground state absorbs a photon, comes to an excited state then emits a photon with a wavelength of 1242 nm. The incident photon must have a wavelength of 414 nm.
C. An atom in the ground state has a collision with an electron, then emits a photon with a wavelength of 1242 nm. The incident electron must have an energy of 3eV.
D. An atom in the ground state absorbs a photon, comes to an excited state then emits a photon with a wavelength of 1242 nm. The incident photon must have a wavelength of 1242 nm.

Answer

A, B

Explanation

(B) `lambda=1242rArr DeltaE=1eV rArr n=3 " " rArr DeltaE' I = 3 eV " " rArr lambda'414nm`
(C) Electron can have 3eV or more.