What happens when the electron in a hydrogen atom flips its direction of spin,starting parallel to the spin of the proton and ending antiparallel to the spin of the proton?
A) Nothing-this is a forbidden transition and never occurs.
B) The atom emits a photon of 656.3 nm wavelength in the red region of the spectrum.
C) The atom emits a photon of 121.5 nm wavelength in the UV region of the spectrum.
D) The atom emits a photon of 21-cm wavelength in the radio region of the spectrum.

Question

Quizplus · Accepted Answer

When the electron in a hydrogen atom flips its spin from being parallel to the proton's spin to being antiparallel, the atom undergoes a transition that results in the emission of a photon with a wavelength of 21 cm. This transition is in the radio frequency range and is significant in astronomy, particularly in the study of interstellar hydrogen clouds.

What Happens When the Electron in a Hydrogen Atom Flips